,transcrib]'s ,notes ,9 ?is ,pla9 ,text v]sion ( ?is e,book1 italics are enclos$ )9 tildas1 sup]scripts & subscripts are enclos$ 9 curly braces & prec$$ by a c>et sup]script or an und]score subscript4 ,o!r notes w be f\nd at ! end ( ?is e,book4 ,,smi?sonian ,,miscellane\s ,,collections ,,volume #gf1 ,,numb] #b ,,hi/ory ,,( ,,electric ,,light ,,by ,,h5ry ,,s*ro$] ,h>rison1 ,new ,j]sey ,illu/ration3 ,,= ,,! ,,increase ,,& ,,diffvsion ,,( ,,k ,,among ,,m5 ,,smi?sonian ,,in/itvtion ,,wa%+ton #ahdf 7,,publication #bgag7 ,,city ,,( ,,wa%+ton ,,publi%$ ,,by ,,! ,,smi?sonian ,,in/itution ,,augu/ #ae1 #aibc ,! ,"l ,baltimore ,press ,,baltimore1 ,,md41 ,u4 ,s4 ,a4 ,,cont5ts ,,page ,li/ ( ,illu/rations v ,=eword ix ,*ronology ( ,electric ,light xi ,e>ly ,records ( ,electricity & ,magnetism #a ,ma*9es ,g5]at+ ,electricity by ,friction #b ,! ,leyd5 ,j> #c ,electricity ,g5]at$ by ,*emical ,means #c ,improvem5t ( ,volta's ,batt]y #e ,davy's ,discov]ies #e ,rese>*es ( ,o]/$1 ,ampre1 ,s*weigg] & ,/urgeon #f ,ohm's ,law #g ,inv5tion ( ! ,dynamo #g ,daniell's ,batt]y #aj ,grove's ,batt]y #aa ,grove's ,demon/ration ( ,inc&esc5t ,light+ #ab ,gr5et ,batt]y #ac ,de ,moleyns' ,inc&esc5t ,lamp #ac ,e>ly ,developm5ts ( ! ,arc ,lamp #ad ,j\le's ,law #af ,/>r's ,inc&esc5t ,lamp #ag ,o!r ,e>ly ,inc&esc5t ,lamps #ai ,fur!r ,arc ,lamp ,developm5ts #bj ,developm5t ( ! ,dynamo1 #ahdj-ahfj #bd ,! ,fir/ ,comm]cial ,in/allation ( an ,electric ,light #be ,fur!r ,dynamo ,developm5ts #bg ,russian ,inc&esc5t ,lamp ,inv5tors #cj ,! ,jablo*k(f 8,c&le0 #ca ,comm]cial ,introduction ( ! ,diff]5tially ,controll$ ,arc ,lamp #cc ,arc ,light+ 9 ! ,unit$ ,/ates #cc ,o!r ,am]ican ,arc ,light ,sy/ems #dj 8,sub-,divid+ ! ,electric ,light0 #db ,edison's ,inv5tion ( a ,practical ,inc&esc5t ,lamp #dc ,edison's ,?ree-,wire ,sy/em #ec ,developm5t ( ! ,alt]nat+ ,curr5t ,con/ant ,pot5tial ,sy/em #ed ,inc&esc5t ,lamp ,developm5ts1 #ahhd-ahid #ef ,! ,edison 8,municipal0 ,/reet ,light+ ,sy/em #fb ,! ,%unt ,box ,sy/em = ,s]ies ,inc&esc5t ,lamps #fd ,! ,enclos$ ,arc ,lamp #fe ,! ,flame ,arc ,lamp #fg ,! ,con/ant ,curr5t ,trans=m] = ,s]ies ,circuits #fi ,enclos$ ,s]ies ,alt]nat+ ,curr5t ,arc ,lamps #fi ,s]ies ,inc&esc5t ,lamps on ,con/ant ,curr5t ,trans=m]s #gj ,! ,n]n/ ,lamp #ga ,! ,coop]-,hewitt ,lamp #gb ,! ,lum9\s or ,magnetite ,arc ,lamp #gd ,m]cury ,arc ,rectifi] = ,magnetite ,arc ,lamps #gg ,inc&esc5t ,lamp ,developm5ts1 #ahid-aijd #gh ,! ,moore ,tube ,light #gi ,! ,osmium ,lamp #hb ,! ,gem ,lamp #hb ,! ,tantalum ,lamp #hd ,inv5tion ( ! ,tung/5 ,lamp #he ,drawn ,tung/5 ,wire #hg ,! ,qu>tz ,m]cury ,vapor ,arc ,lamp #hh ,! ,gas-,fill$ ,tung/5 ,lamp #hi ,types & ,sizes ( ,tung/5 ,lamps ,n[ ,made #ia ,/&>d ,voltages #ic ,co/ ( ,inc&esc5t ,electric ,light #ic ,/ati/ics ,reg>d+ ! ,pres5t ,dem& = ,lamps #id ,select$ ,bibliography #ie ,,li/ ,,( ,,illu/rations ,,page ,portion ( ! ,electrical ,exhibit 9 ! ,unit$ ,/ates ,national ,museum viii ,otto ,von ,gu]icke's ,electric ,ma*9e1 #afej #b ,voltaic ,pile1 #agii #d ,f>aday's ,dynamo1 #ahca #h ,pixii's ,dynamo1 #ahcb #i ,daniell's ,cell1 #ahcf #aj ,grove's ,cell1 #ahch #aa ,grove's ,inc&esc5t ,lamp1 #ahdj #ac ,de ,moleyns' ,inc&esc5t ,lamp1 #ahda #ad ,wright's ,arc ,lamp1 #ahde #ae ,ar*]eau's ,arc ,lamp1 #ahdh #af ,/>r's ,inc&esc5t ,lamp1 #ahde #ah ,/aite's ,inc&esc5t ,lamp1 #ahdh #ai ,rob]ts' ,inc&esc5t ,lamp1 #aheb #ai ,f>m]'s ,inc&esc5t ,lamp1 #ahei #bj ,rob]ts' ,arc ,lamp1 #aheb #ba ,slat] & ,watson's ,arc ,lamp1 #aheb #ba ,diagram ( 8,diff]5tial0 ,me?od ( ,control ( an ,arc ,lamp #bb ,lacassagne & ,?i]s' ,diff]5tially ,controll$ ,arc ,lamp1 #ahef #bc ,s]r9's ,arc ,lamp1 #aheg #bd ,siem5s' ,dynamo1 #ahef #be ,alliance ,dynamo1 #ahfb #bf ,:eat/one's ,self-,excit$ ,dynamo1 #ahff #bg ,gramme's ,dynamo1 #ahga #bh ,gramme's 8,r+0 ,armature #bh ,alt5eck's ,dynamo ) 8,drum0 ,w\nd ,armature1 #ahgb #bi ,lodygu9e's ,inc&esc5t ,lamp1 #ahgb #cj ,konn's ,inc&esc5t ,lamp1 #ahge #cj ,b\ligu9e's ,inc&esc5t ,lamp1 #ahgf #ca ,jablo*k(f 8,c&le10 #ahgf #cb ,jablo*k(f's ,alt]nat+ ,curr5t ,dynamo1 #ahgf #cc ,wallace-,f>m] ,arc ,lamp1 #ahge #cd ,wallace-,f>m] ,dynamo1 #ahge #cd ,we/on's ,arc ,lamp1 #ahgf #ce ,bru%'s ,dynamo1 #ahgg #cf ,diagram ( ,bru% ,armature #cf ,bru%'s ,arc ,lamp1 #ahgg #cg ,?omson-,h\/on ,arc ,dynamo1 #ahgh #ch ,diagram ( ,t-,h ,arc ,light+ ,sy/em #ci ,?omson-,h\/on ,arc ,lamp1 #ahgh #dj ,?omson ,d\ble ,c>bon ,arc ,lamp #dj ,maxim ,dynamo #da ,sawy]'s ,inc&esc5t ,lamp1 #ahgh #db ,f>m]'s ,inc&esc5t ,lamp1 #ahgh #db ,maxim's ,inc&esc5t ,lamp1 #ahgh #dc ,edison's ,fir/ ,exp]im5tal ,lamp1 #ahgh #dd ,diagram ( ,con/ant ,curr5t ,s]ies ,sy/em #de ,diagram ( ,edison's ,multiple ,sy/em1 #ahgi #de ,edison ,dynamo1 #ahgi #df ,edison's ,high ,resi/ance ,plat9um ,lamp1 #ahgi #dg ,edison's ,high ,resi/ance ,plat9um 9 ,vacuum ,lamp1 #ahgi #dg ,edison's ,c>bon ,lamp ( ,octob] #ba1 #ahgi #dh ,demon/ration ( ,edison's ,inc&esc5t ,light+ ,sy/em #di ,dynamo ,room1 ,s4 ,s4 ,columbia #ej ,orig9al ,socket = ,inc&esc5t ,lamps #ea ,wire ,t]m9al ,base ,lamp1 #ahhj #ea ,orig9al ,screw ,base ,lamp1 #ahhj #eb ,improv$ ,screw ,base ,lamp1 #ahha #eb ,f9al ,=m ( ,screw ,base1 #ahha #ec ,diagram ( ,edison's ,?ree ,wire ,sy/em1 #ahha #ed ,diagram ( ,/anley's ,alt]nat+ ,curr5t ,multiple ,sy/em1 #ahhe #ee ,/&>d ,edison ,lamp1 #ahhd #ef ,/&>d ,edison ,lamp1 #ahhh #ef ,/&>d ,edison ,lamp1 #ahid #eg ,v>i\s ,bases 9 ,use1 #ahib #eh ,?omson-,h\/on ,socket #ei ,we/+h\se ,socket #ei ,adapt]s = ,edison ,screw ,sockets1 #ahib #fj ,v>i\s ,s]ies ,bases 9 ,use1 #ahib #fa ,edison 8,municipal0 ,sy/em1 #ahhe #fb ,edison 8,municipal0 ,lamp1 #ahhe #fc ,%unt ,box ,sy/em1 #ahhg #fd ,enclos$ ,arc ,lamp1 #ahic #fe ,op5 ,flame ,arc ,lamp1 #ahih #ff ,enclos$ ,flame ,arc ,lamp1 #aijh #ff ,con/ant ,curr5t ,trans=m]1 #aijj #fh ,s]ies ,inc&esc5t ,lamp ,socket ) ,film ,cut\t1 #aijj #gj ,n]n/ ,lamp1 #aijj #ga ,diagram ( ,n]n/ ,lamp #gb ,coop]-,hewitt ,m]cury ,vapor ,arc ,lamp1 #aija #gc ,diagram ( ,coop]-,hewitt ,lamp = ,use on ,alt]nat+ ,curr5t #gd ,lum9\s or ,magnetite ,arc ,lamp1 #aijb #ge ,diagram ( ,s]ies ,magnetite ,arc ,lamp #gf ,m]cury ,arc ,rectifi] ,tube = ,s]ies ,magnetite ,arc ,circuits1 #aijb #gg ,e>ly ,m]cury ,arc ,rectifi] ,in/allation #gh ,! ,moore ,tube ,light1 #aijd #gi ,diagram ( ,fe$] ,valve ( ,moore ,tube #hj ,osmium ,lamp1 #aije #hb ,gem ,lamp1 #aije #hc ,tantalum ,lamp1 #aijf #hd ,tung/5 ,lamp1 #aijg #hf ,drawn ,tung/5 ,wire ,lamp1 #aiaa #hg ,qu>tz ,m]cury ,vapor ,lamp1 #aiab #hh ,gas ,fill$ ,tung/5 ,lamp1 #aiac #hi ,gas ,fill$ ,tung/5 ,lamp1 #aibc #ij ,/&>d ,tung/5 ,lamps1 #aibc #ib ,illu/ration3 ,,portion ,,( ,,! ,,electrical ,,exhibit ,,9 ,,! ,,unit$ ,,/ates ,,national ,,museum4 ,section devot$ to ! hi/orical developm5t ( ! electric light & dynamo4 ,,=eword ,9 ! ye> #ahhd a ,section ( ,transportation 0 organiz$ 9 ! ,unit$ ,/ates ,national ,museum = ! purpose ( prep>+ & assembl+ educational exhibits ( a few objects ( railroad ma*9]y :i* _h be5 obta9$ bo? f ! ,c5t5nial ,exhibition held 9 ,philadelphia 9 #ahgf & /ill e>li] z incid5tals to e?nological collections1 & to secure o!r collections relat+ to ! railway indu/ry4 ,f ?is beg9n+ ! section 0 exp&$ to include ! :ole field ( eng9e]+ & is designat$ at pres5t z ! ,divisions ( ,m9]al & ,me*anical ,te*nology4 ,! gr[? & enl>gem5t ( ! collections has be5 p>ticul>ly m>k$ 9 ! fields ( m9+ & m9]al indu/ries2 me*anical eng9e]+1 especially p]ta9+ to ! /eam eng9e1 int]nal combu/ion eng9e & locomotive2 naval ar*itecture1 & electrical eng9e]+1 p>ticul>ly ! developm5t ( ! telegraph1 telephone & ! electric light4 ,9 ! acquisition ( objects visualiz+ ! hi/ory ( electric light ! ,museum has be5 r =tunate1 p>ticul>ly z reg>ds ! developm5ts 9 ! ,unit$ ,/ates4 ,?us m5tion may be made ( ! orig9al ,pat5t ,(fice models ( ! m important dynamos1 arc lights & inc&esc5t lights1 toge!r ) orig9al comm]cial app>atus aft] ^! models2 a unit ( ! equipm5t us$ 9 ! fir/ comm]cially successful in/allation on l& ( an inc&esc5t light+ sy/em1 pres5t$ by ,joseph ,e4 ,h9ds 9 ^: engrav+ e/abli%m5t 9 ,new ,york ,city ! in/allation 0 made 9 #ahha2 & a l>ge s]ies ( inc&esc5t lights1 ma9ly orig9als1 visualiz+ *ronologically ! developm5ts ( ! ,edison light f its inception1 pres5t$ at int]vals s9ce ! ye> #ahih by ! ,g5]al ,electric ,company4 ,! object ( all collections 9 ! ,divisions is to visualize broadly ! /eps by :i* advances h be5 made 9 ea* field ( eng9e]+2 to %[ ! layman ! fundam5tal & g5]al pr9ciples :i* are ! basis = ! developm5ts2 & to famili>ize ! eng9e] ) bran*es ( eng9e]+ o!r ?an 8 own4 ,normally :5 a subject is completely cov]$ by a collection ( objects1 a pap] is prep>$ & publi%$ describ+ ! collection & ! /ory x portrays4 ,9 ! pres5t in/ance1 h[ev]1 on acc\nt ( ! unc]ta9ty ( ! "t ( complet+ ! collection1 if x is possible ev] to br+ ?is ab\t1 x 0 ?\ght advisable to publi% ,mr4 ,s*ro$]'s pap] :i* draws ^u ! ,museum collection z completely z possible4 ,,c>l ,w4 ,,mitman1 ,curator1 ,divisions ( ,m9]al & ,me*anical ,te*nology1 ,u4 ,s4 ,national ,museum4 ,,*ronology ,,( ,,electric ,,light #ahjj--;,alles&ro ,volta demon/rat$ 8 discov]y t electricity c be g5]at$ by *emical means4 ,! ,,volt1 ! unit ( electric pressure1 is nam$ 9 8 honor = ?is discov]y ( ! electric batt]y4 #ahjb--,sir ,humphry ,davy demon/rat$ t electric curr5t c heat c>bon & /rips ( metal to inc&esc5ce & give light4 #ahji--,sir ,humphry ,davy demon/rat$ t curr5t w give a brilliant flame betwe5 ! ends ( two c>bon p5cils :i* are fir/ all[$ to t\* ea* o!r & !n pull$ ap>t4 ,?is light he call$ ! 8arc0 on acc\nt ( its ar* %ape4 #ahbj--;,&r ,m>ie ,ampre discov]$ t curr5t fl[+ ?r\gh a coil$ wire gives x ! prop]ties ( a magnet4 ,! ,,amp]e1 ! unit ( fl[ ( electric curr5t1 is nam$ 9 8 honor = ?is discov]y4 #ahbe--;,georg ,simon ,ohm discov]$ ! relation betwe5 ! voltage1 amp]eage & resi/ance 9 an electric circuit1 :i* is call$ ,ohm's ,law4 ,! ,,ohm1 ! unit ( electric resi/ance1 is nam$ 9 8 honor = ?is discov]y4 #ahca--,mi*ael ,f>aday discov]$ t electricity c be g5]at$ by mov+ a wire 9 ! neighborhood ( a magnet1 ! pr9ciple ( ! dynamo4 #ahdj--,sir ,william ,rob]t ,grove demon/rat$ 8 exp]im5tal inc&esc5t lamp 9 :i* plat9um is made inc&esc5t by curr5t fl[+ ?r\gh x4 #ahda--;,fr$]ick ,de ,moleyns obta9$ ! fir/ pat5t on an inc&esc5t lamp4 ,! burn] 0 p[d]$ *>coal op]at+ 9 an exhau/$ glass globe4 #ahde--,?omas ,wright obta9$ ! fir/ pat5t on an arc light4 #ahde--;,j4 ,w4 ,/>r inv5t$ an inc&esc5t lamp consi/+ ( a c>bon p5cil op]at+ 9 ! vacuum above a column ( m]cury4 #ahef--;,joseph ,lacassagne & ,h5ry ,?i]s inv5t$ ! 8diff]5tial0 me?od ( control ( ! arc :i* 0 univ]sally us$ tw5ty ye>s lat] :5 ! arc lamp 0 comm]cially e/abli%$4 #ahfb--,! fir/ comm]cial in/allation ( an electric light4 ,an arc light 0 put 9 a ligh?\se 9 ,engl&4 #ahff--,sir ,*>les ,:eat/one inv5t$ ! 8self-excit$0 dynamo1 n[ univ]sally us$4 #ahgb--,lodygu9e inv5t$ an inc&esc5t lamp hav+ a graphite burn] op]at+ 9 nitrog5 gas4 #ahgf--,paul ,jablo*k(f inv5t$ ! 8electric c&le10 an arc light comm]cially us$ = light+ ! b\lev>ds 9 ,p>is4 #ahgg-h--;,arc light sy/ems comm]cially e/abli%$ 9 ! ,unit$ ,/ates by ,william ,wallace & ,pr(4 ,moses ,f>m]1 ,edw>d ,we/on1 ,*>les ,f4 ,bru% & ,pr(4 ,elihu ,?omson & ,edw9 ,j4 ,h\/on4 #ahgi--,?omas ,alva ,edison inv5t$ an inc&esc5t lamp consi/+ ( a high resi/ance c>bon filam5t op]at+ 9 a high vacuum ma9ta9$ by an all glass globe4 ,^! pr9ciples are us$ 9 all inc&esc5t lamps made today4 ,he also inv5t$ a completely new sy/em ( di/ribut+ electricity at con/ant pressure1 n[ univ]sally us$4 #ahhb--,luci5 ,g\l>d & ,john ,d4 ,gibbs inv5t$ a s]ies alt]nat+ curr5t sy/em ( di/ribut+ electric curr5t4 ,?is has n be5 comm]cially us$4 #ahhf--,william ,/anley inv5t$ a con/ant pressure alt]nat+ curr5t sy/em ( di/ribution4 ,?is is univ]sally us$ :]e curr5t is to be di/ribut$ long di/ances4 #ahic--,l\is ,b4 ,m>ks inv5t$ ! enclos$ c>bon arc lamp4 #ahih--;,brem]'s inv5tion ( ! flame arc lamp1 hav+ c>bons impregnat$ ) v>i\s salts1 comm]cially e/abli%$4 #aijj--;,dr4 ,wal!r ,n]n/'s inv5tion ( ! ,n]n/ lamp comm]cially e/abli%$4 ,! burn] consi/$ ( v>i\s oxides1 su* z zirconia1 :i* op]at$ 9 ! op5 air4 #aija--;,dr4 ,pet] ,coop] ,hewitt's inv5tion ( ! m]cury arc light comm]cially e/abli%$4 #aijb--,! magnetite arc lamp 0 develop$ by ,c4 ,a4 ,b4 ,halvorson1 ,jr4 ,?is has a new me?od ( control ( ! arc4 ,! negative electrode consi/s ( a mixture ( magnetite & o!r sub/ances pack$ 9 an iron tube4 #aijd--;,d4 ,mc,farlan ,moore's inv5tion ( ! ,moore vacuum tube light comm]cially e/abli%$4 ,?is consi/$ ( a long tube1 made 9 l5g?s up to #bjj feet1 f :i* ! air _h be5 exhau/$ to ab\t a ?\s&? ( an atmosph]e4 ,high voltage curr5t pass+ ?r\gh ?is r>efi$ atmosph]e caus$ x to gl[4 ,r>efi$ c>bon dioxide gas 0 lat] us$4 #aije--;,dr4 ,au] von ,welsba*'s inv5tion ( ! osmium inc&esc5t lamp comm]cially e/abli%$1 b only on a small scale 9 ,europe4 ,! metal osmium1 us$ = ! filam5t :i* op]at$ 9 vacuum1 is r>] & m exp5sive ?an plat9um4 #aije--;,dr4 ,willis ,r4 ,:itney's inv5tion ( ! ,gem inc&esc5t lamp comm]cially e/abli%$4 ,! c>bon filam5t _h be5 heat$ to a v high temp]ature 9 an electric resi/ance furnace inv5t$ by him4 ,! lamp 0 #be p] c5t m effici5t ?an ! regul> c>bon lamp4 #aijf--;,dr4 ,w]n] von ,bolton's inv5tion ( ! tantalum inc&esc5t lamp comm]cially e/abli%$4 #aijg--;,alex&] ,j & ,franz ,hanaman's inv5tion ( ! tung/5 filam5t inc&esc5t lamp comm]cially e/abli%$4 #aiaa--;,dr4 ,william ,d4 ,coolidge's inv5tion ( drawn tung/5 wire comm]cially e/abli%$4 #aiac--;,dr4 ,irv+ ,langmuir's inv5tion ( ! gas-fill$ tung/5 filam5t inc&esc5t lamp comm]cially e/abli%$4 ,,hi/ory ,,( ,,electric ,,light ,,by ,,h5ry ,,s*ro$]1 ,,h>rison1 ,,new ,,j]sey4 ,,e>ly ,,records ,,( ,,electricity ,,& ,,magnetism ,ab\t tw5ty-five c5turies ago1 ,?ales1 a ,greek philosoph]1 record$ ! fact t if amb] is rubb$ x w attract light objects4 ,! ,greeks call$ amb] 8elektron10 f :i* we get ! ^w 8electricity40 ,ab\t two hundr$ & fifty ye>s lat]1 ,ari/otle1 ano!r ,greek philosoph]1 m5tion$ t ! lode/one w\ld attract iron4 ,lode/one is an iron ore 7,fe#c,o#d71 hav+ magnetic qualities & is n[ call$ magnetite4 ,! ^w 8magnet0 comes f ! fact t ! be/ specim5s ( lode/ones came f ,magnesia1 a city 9 ,asia ,m9or4 ,plut>*1 a ,greek biograph]1 wrote ab\t #ajj ,a4 ,d41 t iron is sometimes attract$ & at o!r times repell$ by a lode/one4 ,?is indicates t ! piece ( iron 0 magnetis$ by ! lode/one4 ,9 #aahj1 ,alex&] ,neckham1 an ,engli% ,monk1 describ$ ! compass1 :i* probably _h be5 inv5t$ by sailors ( ! nor!rn c\ntries ( ,europe1 al?\gh its inv5tion has be5 cr$it$ to ! ,*9ese4 ,e>ly compasses probably consi/$ ( an iron ne$le1 magnetis$ by a lode/one1 m\nt$ on a piece ( wood float+ 9 wat]4 ,! ^w lode/one or 8lead+ /one0 comes f ! fact t x w\ld po9t t[>ds ! nor? if susp5d$ l a compass4 ,william ,gilb]t1 physician to ,que5 ,elizabe? ( ,engl&1 wrote a book ab\t ! ye> #afjj giv+ all ! in=mation !n kn[n on ! subject4 ,he also describ$ 8 exp]im5ts1 %[+1 among o!r ?+s1 ! exi/5ce ( magnetic l9es ( =ce & ( nor? & s\? poles 9 a magnet4 ,rob]t ,norman _h discov]$ a few ye>s previ\sly t a compass ne$le m\nt$ on a horizontal axis w\ld dip d[nw>d4 ,gilb]t cut a l>ge lode/one into a sph]e1 & obs]v$ t ! ne$le did n dip at ! equator ( ?is sph]e1 ! dip increas+ to #ij degrees z ! poles 7 approa*$4 ,f ?is he d$uc$ t ! e>? 0 a magnet ) ! magnetic nor? pole at ! geographic nor? pole4 ,x has s9ce be5 det]m9$ t ^! two poles d n co9cide4 ,gilb]t sugge/$ ! use ( ! dipp+ ne$le to det]m9e latitude4 ,he also discov]$ t o!r sub/ances1 beside amb]1 w\ld attract light objects if rubb$4 ,,ma*9es ,,g5]at+ ,,electricity ,,by ,,friction ,otto ,von ,gu]icke 0 mayor ( ! city ( ,magdeburg z well z a philosoph]4 ,ab\t #afej he made a ma*9e consi/+ ( a ball ( sulphur m\nt$ on a %aft :i* c\ld be rotat$4 ,electricity 0 g5]at$ :5 ! h& 0 press$ aga9/ ! globe z x rotat$4 ,he also discov]$ t electricity c\ld be conduct$ away f ! globe by a *a9 & w\ld appe> at ! o!r end ( ! *a94 ,von ,gu]icke also inv5t$ ! vacuum air pump4 ,9 #agji1 ,francis ,hawksbee1 an ,engli%man1 made a simil> ma*9e1 us+ a holl[ glass globe :i* c\ld be exhau/$4 ,! exhau/$ globe :5 rotat$ at high spe$ & rubb$ by h& w\ld produce a gl[+ light4 ,?is 8electric light0 z x 0 call$1 creat$ great excitem5t :5 x 0 %[n be=e ! ,royal ,society1 a ga!r+ ( sci5ti/s1 9 ,london4 ,illu/ration3 ,,otto ,,von ,,gu]icke',s ,,electric ,,ma*9e1 #afej4 ,a ball ( sulphur 0 rotat$1 electricity be+ g5]at$ :5 x rubb$ aga9/ ! h&4 ,/eph5 ,gray1 tw5ty ye>s lat]1 %[$ ! ,royal ,society t electricity c\ld be conduct$ ab\t a ?\s& feet by a hemp ?read1 support$ by silk ?reads4 ,if metal supports 7 us$1 ?is c\ld n be done4 ,*>les du ,fay1 a ,fr5*man1 repeat$ ,gray's exp]im5ts1 & %[$ 9 #agcc t ! sub/ances :i* 7 insulators1 & :i* ,gilb]t _h discov]$1 w\ld become electrifi$ if rubb$4 ,^? sub/ances :i* ,gilb]t c\ld n electrify 7 conductors ( electricity4 ,,! ,,leyd5 ,,j> ,! ?\ght came to ,von ,klei/1 ,bi%op ( ,pom]ania1 ,g]many1 ab\t #agde1 t electricity c\ld be /or$4 ,! frictional ma*9es g5]at$ s small an am\nt ( electricity 7?\gh1 z is n[ kn[n1 at a v high pressure--sev]al ?\s& volts7 t he ?\ght he c\ld increase ! quantity by /or+ x4 ,kn[+ t glass 0 an insulator & wat] a conductor1 he fill$ a glass bottle p>tly full ( wat] ) a nail 9 ! cork to connect ! ma*9e ) ! wat]4 ,hold+ ! bottle 9 "o h& & turn+ ! ma*9e ) ! o!r = a few m9utes1 he !n disconnect$ ! bottle f ! ma*9e4 ,:5 he t\*$ ! nail ) 8 o!r h& he receiv$ a %ock :i* ne>ly /unn$ him4 ,?is 0 call$ ! ,leyd5 j>1 ! =]unn] ( ! pres5t cond5s]4 ,x receiv$ its "n f ! fact t its discov]y 0 also made a %ort "t aft] by exp]im5t]s 9 ! ,univ]sity ( ,leyd54 ,fur!r exp]im5ts %[$ t ! h& hold+ ! bottle 0 z ess5tial z ! wat] inside1 s ^! 7 sub/itut$ by t9 foil coat+s inside & outside ! bottle4 ,b5jam9 ,frankl91 ,am]ican /atesman1 sci5ti/ & pr9t]1 made num]\s exp]im5ts ) ! ,leyd5 j>4 ,he connect$ sev]al j>s 9 p>allel1 z he call$ x1 :i* gave a dis*>ge /rong en\gh to kill a turkey4 ,he also connect$ ! j>s 9 s]ies1 or 89 cascade0 z he call$ x1 ?us e/abli%+ ! pr9ciple ( p>allel & s]ies connections4 ,notic+ ! simil>ity betwe5 ! electric sp>k & lightn+1 ,frankl9 9 #ageb1 p]=m$ 8 fam\s kite exp]im5t4 ,fly+ a kite 9 a ?und]/orm1 he drew electricity f ! cl\ds to *>ge ,leyd5 j>s1 :i* 7 lat] dis*>g$1 prov+ t lightn+ & electricity 7 ! same4 ,?is l$ him to inv5t ! lightn+ rod4 ,,electricity ,,g5]at$ ,,by ,,*emical ,,means ,luigi ,galvani 0 an ,italian sci5ti/4 ,ab\t #aghe1 s ! /ory goes1 8 wife 0 9 delicate heal?1 & "s frog legs 7 be+ sk9n$ to make h] a n\ri%+ s\p4 ,an assi/ant hold+ ! legs ) a metal clamp & cutt+ ! sk9 ) a scalpel1 happ5$ to let ! clamp & scalpel t\* ea* o!r4 ,to 8 amazem5t ! frog legs twit*$4 ,galvani repeat$ ! exp]im5t _m times by t\*+ ! n]ve ) a metal rod & ! muscle ) a diff]5t metal rod & all[+ ! rods to t\*1 & prop\nd$ ! !ory ( animal electricity 9 a pap] he publi%$ 9 #agia4 ,alles&ro ,volta1 a pr(essor ( physics 9 ! ,univ]sity ( ,pavia1 ,italy1 read ab\t ,galvani's "w & repeat$ 8 exp]im5ts4 ,he f\nd t ! ext5t ( ! movem5t ( ! frog legs dep5d$ on ! metals us$ = ! rods1 & ?us believ$ t ! electric *>ge 0 produc$ by ! contact ( dissimil> metals ) ! moi/ure 9 ! muscles4 ,to prove 8 po9t he made a pile ( silv] & z9c discs ) clo?s1 wet ) salt wat]1 betwe5 !m4 ,?is 0 9 #agii1 & he describ$ 8 pile 9 ,m>*1 #ahjj1 9 a lett] to ! ,royal ,society 9 ,london4 ,illu/ration3 ,,voltaic ,,pile1 #agii4 ,volta discov]$ t electricity c\ld be g5]at$ by *emical means & made a pile ( silv] & z9c discs ) clo?s1 wet ) salt wat]1 betwe5 !m4 ,?is 0 ! =]unn] ( ! pres5t-day dry batt]y4 ,photograph c\rtesy ,pr(4 ,*as4 ,f4 ,*&l] ,museum1 ,columbia ,univ]sity1 ,new ,york4 ,?is 0 an epo*-mak+ discov]y z x 0 ! =]unn] ( ! pres5t-day prim>y batt]y4 ,volta soon f\nd t ! g5]ation ( electricity became weak] z ! clo?s became dry1 s to ov]come ?is he made 8 8cr[n ( cups40 ,?is consi/$ ( a s]ies ( cups conta9+ salt wat] 9 :i* /rips ( silv] & z9c 7 dipp$4 ,ea* /rip ( silv] 9 "o cup 0 connect$ to ! z9c /rip 9 ! next cup1 ! end /rips ( silv] & z9c be+ t]m9als ( ! batt]y4 ,?is 0 ! fir/ "t t a cont9u\s supply ( electricity 9 reasonable quantities 0 made available1 s ! ,,volt1 ! unit ( electrical pressure 0 nam$ 9 8 honor4 ,x 0 lat] %[n t ! *emical aff9ity ( "o ( ! metals 9 ! liquid 0 conv]t$ into electric en]gy4 ,! *emical action ( ,volta's batt]y is t ! salt wat] attacks ! z9c :5 ! circuit is clos$ =m+ z9c *loride1 cau/ic soda & hydrog5 gas4 ,! *emical equation is3 ,zn #b,na,cl #b;,h#b,o ,zn,cl#b #b,na,o,h ,h#b ,,improvem5t ,,( ,,volta',s ,,batt]y ,x 0 e>ly sugge/$ t %eets ( silv] & z9c be sold]$ toge!r back to back & t a tr\gh be divid$ into cells by ^! bimetal %eets be+ put into grooves cut 9 ! sides & bottom ( ! tr\gh4 ,?is is ! reason :y "o unit ( a batt]y is call$ a 8cell40 ,x 0 soon f\nd t a m p[]ful cell c\ld be made if copp]1 z9c & dilute sulphuric acid 7 us$4 ,! z9c is dissolv$ by ! acid =m+ z9c sulphate & hydrog5 gas1 ?us3 ,zn ,h#b,,s#d ,zn,s,o#d ,h#b ,! hydrog5 gas appe>s z bubbles on ! copp] & r$uces ! op5 circuit voltage 7ab\t #j4h volt p] cell7 z curr5t is tak5 f ! batt]y4 ,?is is call$ 8pol>ization40 ,ow+ to m9ute impurities 9 ! z9c1 x is attack$ by ! acid ev5 :5 no curr5t is tak5 f ! batt]y1 ! impurities =m+ ) ! z9c a %ort circuit$ local cell4 ,?is is call$ 8local action10 & ?is difficulty 0 at fir/ ov]come by remov+ ! z9c f ! acid :5 ! batt]y 0 n 9 use4 ,,davy',s ,,discov]ies ,sir ,humphry ,davy 0 a well-kn[n ,engli% *emi/1 & ) ! aid ( p[]ful batt]ies con/ruct$ = ! ,royal ,in/itution 9 ,london1 he made num]\s exp]im5ts on ! *emical effects ( electricity4 ,he decompos$ a numb] ( sub/ances & discov]$ ! elem5ts boron1 potassium & sodium4 ,he heat$ /rips ( v>i\s metals to inc&esc5ce by pass+ curr5t ?r\gh !m1 & %[$ t plat9um w\ld /ay inc&esc5t = "s "t )\t oxidiz+4 ,?is 0 ab\t #ahjb4 ,9 ! e>ly frictional ma*9es1 ! pres5ce ( electricity 0 %[n by ! fact t sp>ks c\ld be obta9$4 ,simil>ly ! break+ ( ! circuit ( a batt]y w\ld give a sp>k4 ,davy1 ab\t #ahji1 demon/rat$ t ?is sp>k c\ld be ma9ta9$ = a long "t ) ! l>ge batt]y ( #bjjj cells he _h _h con/ruct$4 ,us+ two /icks ( *>coal connect$ by wires to ! t]m9als ( ?is v p[]ful batt]y1 he demon/rat$ be=e ! ,royal ,society ! light produc$ by t\*+ ! /icks toge!r & !n hold+ !m ap>t horizontally ab\t ?ree in*es4 ,! brilliant flame obta9$ he call$ an 8arc0 because ( its ar* %ape1 ! heat$ gases1 ris+1 assum+ ?is =m4 ,davy 0 giv5 ! degree ( ,,ll4 ,d4 = 8 di/+ui%$ rese>* "w1 & 0 knight$ on ! eve ( 8 m>riage1 ,april #aa1 #ahab4 ,,rese>*es ,,( ,,o]/$1 ,,amp,,re1 ,,s*weigg] ,,& ,,/urgeon ,hans ,*ri/ian ,o]/$ 0 a pr(essor ( physics at ! ,univ]sity ( ,cop5hag5 9 ,d5m>k4 ,"o day 9 #ahai1 :ile address+ 8 /ud5ts1 he happ5$ to hold a wire1 ?r\gh :i* curr5t 0 fl[+1 ov] a l>ge compass4 ,to 8 surprise he saw ! compass 0 deflect$ f its true position4 ,he promptly made a numb] ( exp]im5ts & discov]$ t by rev]s+ ! curr5t ! compass 0 deflect$ 9 ! opposite direction4 ,o]/$ ann\nc$ 8 discov]y 9 #ahbj4 ,&r ,m>ie ,ampre 0 a pr(essor ( ma!matics 9 ! ,ecole ,polyte*nic 9 ,p>is4 ,he>+ ( ,o]/$'s discov]y1 he imm$iately made "s exp]im5ts & made ! fur!r discov]y 9 #ahbj t if ! wire is coil$ & curr5t pass$ ?r\gh x1 ! coil _h all ! prop]ties ( a magnet4 ,^! two discov]ies l$ to ! inv5tion ( ,s*weigg] 9 #ahbj1 ( ! galvanomet] 7or 8multipli]0 z x 0 !n call$71 a v s5sitive in/rum5t = measur+ electric curr5ts4 ,x consi/$ ( a delicate compass ne$le susp5d$ 9 a coil ( _m turns ( wire4 ,curr5t 9 ! coil deflect$ ! ne$le1 ! direction & am\nt ( deflection indicat+ ! direction & /r5g? ( ! curr5t4 ,ampre fur!r made ! discov]y t curr5ts 9 opposite directions repel & 9 ! same directions attract ea* o!r4 ,he also gave a rule = det]m9+ ! direction ( ! curr5t by ! deflection ( ! compass ne$le4 ,he develop$ ! !ory t magnetism is caus$ by electricity fl[+ ar\nd ! circumf]5ce ( ! body magnetis$4 ,! ,,amp]e1 ! unit ( fl[ ( electric curr5t1 0 nam$ 9 honor ( 8 discov]ies4 ,9 #ahbe x 0 %[n by ,/urgeon t if a b> ( iron 7 plac$ 9 ! coil1 its magnetic /r5g? w\ld be v greatly increas$1 :i* he call$ an electro-magnet4 ,,ohm',s ,,law ,georg ,simon ,ohm 0 born 9 ,bav>ia1 ! olde/ son ( a poor blacksmi?4 ,) ! aid ( fri5ds he w5t to college & became a tea*]4 ,x _h be5 %[n t ! rate ( transf] ( heat f "o end to ! o!r ( a metal b> is proportional to ! diff]5ce ( temp]ature betwe5 ! ends4 ,ab\t #ahbe1 ,ohm1 by analogy & exp]im5t1 f\nd t ! curr5t 9 a conductor is proportional to ! diff]5ce ( electric pressure 7voltage7 betwe5 its ends4 ,he fur!r %[$ t ) a giv5 diff]5ce ( voltage1 ! curr5t 9 diff]5t conductors is inv]sely proportional to ! resi/ance ( ! conductor4 ,ohm !re=e prop\nd$ ! law t ! curr5t fl[+ 9 a circuit is equal to ! voltage on t circuit divid$ by ! resi/ance ( ! circuit4 ,9 honor ( ?is discov]y1 ! unit ( electrical resi/ance is call$ ! ,,ohm4 ,?is law is usually express$ z3 ,c ,e_/,r 8,c0 mean+ curr5t 79 amp]es71 8,e0 mean+ electromotive =ce or voltage 79 volts7 & 8,r0 mean+ resi/ance 79 ohms74 ,?is is "o ( ! fundam5tal laws ( electricity & if ?or\ghly und]/ood1 w solve _m electrical problems4 ,?us1 if any two ( ! above units are kn[n1 ! ?ird c be det]m9$4 ,examples3 ,an inc&esc5t lamp on a #abj-volt circuit consumes #j4d amp]e1 h5ce its resi/ance "u su* conditions is #cjj ohms4 ,sev]al trolley c>s at ! end ( a l9e take #ajj amp]es to run !m & ! resi/ance ( ! ov]head wire f ! p[] h\se to ! trolley c>s is half an ohm2 ! drop 9 voltage on ! l9e betwe5 ! p[] h\se & trolley c>s is !re=e #ej volts1 s t if ! voltage at ! p[] h\se 7 #fjj1 x w\ld be #eej volts at ! end ( ! l9e4 ,critics d]id$ ,ohm's law s t he 0 =c$ out ( 8 position z tea*] 9 ! ,high ,s*ool 9 ,cologne4 ,f9ally aft] t5 ye>s ,ohm began to f9d support]s & 9 #ahda 8 law 0 publicly recogniz$ by ! ,royal ,society ( ,london :i* pres5t$ him ) ! ,copley m$al4 ,,inv5tion ,,( ,,! ,,dynamo ,mi*ael ,f>aday 0 an ,engli% sci5ti/4 ,born ( p>5ts 9 poor circum/ances1 he became a bookb9d] & /udi$ books on electricity & *emi/ry4 ,he f9ally obta9$ a position z laboratory assi/ant to ,sir ,humphry ,davy help+ him ) 8 lectures & exp]im5ts4 ,he also made a numb] ( exp]im5ts himself & succe$$ 9 liquify+ *lor9e gas = :i* he 0 elect$ to a ,fell[%ip 9 ! ,royal ,in/itution 9 #ahbd4 ,foll[+ up ,o]/$'s & ,ampre's "w1 he endeavor$ to f9d ! relation betwe5 electricity & magnetism4 ,f9ally on ,oct4 #ag1 #ahca1 he made ! exp]im5t ( mov+ a p]man5t b> magnet 9 & out ( a coil ( wire connect$ to a galvanomet]4 ,?is g5]at$ electricity 9 ! coil :i* deflect$ ! galvanomet] ne$le4 ,a few days aft]1 ,oct4 #bh1 #ahca1 he m\nt$ a copp] disk on a %aft s t ! disk c\ld be rotat$ betwe5 ! poles ( a p]man5t horse%oe magnet4 ,! %aft & edge ( ! disk 7 connect$ by bru%es & wires to a galvanomet]1 ! ne$le ( :i* 0 deflect$ z ! disk 0 rotat$4 ,a pap] on 8 inv5tion 0 read be=e ! ,royal ,society on ,novemb] #bd1 #ahca1 :i* appe>$ 9 pr9t$ =m 9 ,janu>y1 #ahcb4 ,illu/ration3 ,,f>aday',s ,,dynamo1 #ahca4 ,f>aday discov]$ t electricity c\ld be g5]at$ by means ( a p]man5t magnet4 ,?is pr9ciple is us$ 9 all dynamos4 ,f>aday did n develop 8 inv5tion any fur!r1 be+ satisfi$1 z 9 all 8 "w1 9 pure rese>*4 ,8 0 a notable inv5tion b x rema9$ = o!rs to make x practicable4 ,hippolyte ,pixii1 a ,fr5*man1 made a dynamo 9 #ahcb consi/+ ( a p]man5t horse%oe magnet :i* c\ld be rotat$ betwe5 two wire bobb9s m\nt$ on a s(t iron core4 ,! wires f ! bobb9s 7 connect$ to a pair ( bru%es t\*+ a commutator m\nt$ on ! %aft hold+ ! magnet1 & o!r bru%es c>ri$ ! curr5t f ! commutator s t ! alt]nat+ curr5t g5]at$ 0 rectifi$ into direct curr5t4 ,illu/ration3 ,,pixii',s ,,dynamo1 #ahcb4 ,pixii made an improvem5t by rotat+ a p]man5t magnet 9 ! neighborhood ( coils ( wire m\nt$ on a s(t iron core4 ,a commutator rectifi$ ! alt]nat+ curr5t g5]at$ into direct curr5t4 ,?is dynamo is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,e4 ,m4 ,cl>ke1 an ,engli%man made1 9 #ahcd1 ano!r dynamo 9 :i* ! bobb9s rotat$ alongside ( ! poles ( a p]man5t horse%oe magnet4 ,he also made a commutator s t ! ma*9e produc$ direct curr5t4 ,none ( ^! ma*9es gave m ?an feeble curr5t at l[ pressure4 ,! l>ge prim>y batt]ies t _h be5 made 7 mu* m p[]ful1 al?\gh exp5sive to op]ate4 ,x has be5 e/imat$ t ! co/ ( curr5t f ! #bjjj-;cell batt]y to op]ate ! demon/ration ( ! arc light by ,davy1 0 six doll>s a m9ute4 ,at pres5t retail rates = electricity sold by light+ companies1 six doll>s w\ld op]ate ,davy's arc light ab\t #ejj h\rs or #cj1jjj times z long4 ,,daniell',s ,,batt]y ,illu/ration3 ,,daniell',s ,,cell1 #ahcf4 ,daniell inv5t$ a batt]y consi/+ ( z9c1 copp] & copp] sulphate4 ,lat] ! por\s cup 0 disp5s$ )1 :i* 0 us$ to keep ! sulphuric acid =m$ sep>ate f ! solution ( copp] sulphate1 ! two liquids !n be+ kept ap>t by _! diff]5ce 9 specific gravity4 ,x 0 !n call$ ! ,gravity ,batt]y & = ye>s 0 us$ 9 telegraphy4 ,x 0 soon discov]$ t if ! z9c electrode 7 rubb$ ) m]cury 7amalgamat$71 ! local action w\ld practically cease1 & if ! hydrog5 bubbles 7 remov$1 ! op]at+ voltage ( ! cell w\ld be increas$4 ,john ,fr$]ic ,daniell1 an ,engli% *emi/1 inv5t$ a cell 9 #ahcf to ov]come ^! difficulties4 ,8 cell consi/$ ( a glass j> conta9+ a saturat$ solution ( copp] sulphate 7,cu,s,o#d74 ,a copp] cyl9d]1 op5 at bo? ends & p]=at$ ) holes1 0 put into ?is solution4 ,on ! outside ( ! copp] cyl9d] !re 0 a copp] r+1 locat$ bel[ ! surface ( ! solution1 act+ z a %elf to support cry/als ( copp] sulphate4 ,inside ! cyl9d] !re 0 a por\s e>!nw>e j> conta9+ dilute sulphuric acid & an amalgamat$ z9c rod4 ,! two liquids 7 !re=e kept ap>t b 9 contact ) ea* o!r ?r\gh ! pores ( ! j>4 ,! hydrog5 gas giv5 (f by ! action ( ! sulphuric acid on ! z9c1 comb9$ ) ! dissolv$ copp] sulphate1 =m$ sulphuric acid & metallic copp]4 ,! latt] 0 deposit$ on ! copp] cyl9d] :i* act$ z ! o!r electrode4 ,?us ! copp] sulphate act$ z a depol>iz]4 ,! *emical reactions 9 ?is cell are1 ,9 inn] por\s j>3 ,zn ,h#b,,s#d ,zn,s,o#d ,h#b ,9 out] glass j>3 ,h#b ,cu,s,o#d ,h#b,,s#d ,cu ,?is cell _h an op5 circuit voltage ( a little ov] "o volt4 ,lat] ! por\s cup 0 disp5s$ )1 ! two liquids be+ kept ap>t by ! diff]5ce ( _! specific gravities4 ,?is 0 kn[n z ! ,gravity cell1 & = ye>s 0 us$ 9 telegraphy4 ,illu/ration3 ,,grove',s ,,cell1 #ahch4 ,?is consi/$ ( z9c1 sulphuric acid1 nitric acid & plat9um4 ,x made a v p[]ful batt]y4 ,! nitric acid is call$ ! depol>iz] z x absorbs ! hydrog5 gas =m$1 ?us improv+ ! op]at+ voltage4 ,,grove',s ,,batt]y ,sir ,william ,rob]t ,grove1 an ,engli% ,judge & sci5ti/1 inv5t$ a cell 9 #ahch consi/+ ( a plat9um electrode 9 /rong nitric acid 9 a por\s e>!nw>e j>4 ,?is j> 0 put 9 dilute sulphuric acid 9 a glass j> 9 :i* !re 0 an amalgamat$ z9c plate = ! o!r electrode4 ,?is _h an op5 circuit voltage ( ab\t #a4i volts4 ,! por\s j> 0 us$ to prev5t ! nitric acid f attack+ ! z9c4 ,! nitric acid 0 us$ = ! purpose ( comb9+ ) ! hydrog5 gas set free by ! action ( ! sulphuric acid on ! z9c1 & h5ce 0 ! depol>iz+ ag5t4 ,hydrog5 comb9+ ) nitric acid =ms nitr\s p]oxide & wat]4 ,"p ( ! nitr\s p]oxide is dissolv$ 9 ! wat]1 & ! re/ escapes z fumes :i*1 h[ev]1 are v suffocat+4 ,! *emical equations ( ?is cell are z foll[s3 ,9 out] glass j>3 ,zn ,h#b,,s#d ,zn,s,o#d ,h#b ,9 inn] por\s j>3 ,h#b #b;,,hno#c ,n#b,o#d #b;,h#b,o ,an int]e/+ ?+ ab\t ,grove's cell is t x 0 plann$ 9 accordance ) a !ory4 ,grove knew t ! electrical en]gy ( ! z9c-sulphuric acid cell came f ! *emical aff9ity ( ! two reag5ts1 & if ! hydrog5 gas set free c\ld be comb9$ ) oxyg5 7to =m wat]--,h#b,o71 su* *emical aff9ity %\ld increase ! /r5g? ( ! cell4 ,z ! hydrog5 gas appe>s at ! o!r electrode1 ! oxidiz+ ag5t %\ld surr\nd t electrode4 ,nitric acid 0 kn[n at t "t z "o ( ! mo/ p[]ful oxidiz+ liquids1 b z x attacks copp]1 he us$ plat9um = ! o!r electrode4 ,?us he n only ov]came ! difficulty ( pol>ization by ! hydrog5 gas1 b also increas$ ! voltage ( ! cell by ! add$ *emical action ( ! comb9ation ( hydrog5 & oxyg54 ,,grove',s ,,demon/ration ,,( ,,inc&esc5t ,,light+ ,9 #ahdj ,grove made an exp]im5tal lamp by atta*+ ! ends ( a coil ( plat9um wire to copp] wires1 ! l[] p>ts ( :i* 7 well v>ni%$ = insulation4 ,! plat9um wire 0 cov]$ by a glass tumbl]1 ! op5 end set 9 a glass di% p>tly fill$ ) wat]4 ,?is prev5t$ draughts ( air f cool+ ! inc&esc5t plat9um1 & ! small am\nt ( oxyg5 ( ! air 9 ! tumbl] r$uc$ ! am\nt ( oxidization ( ! plat9um t w\ld o!rwise occur4 ,) curr5t suppli$ by a l>ge numb] ( cells ( 8 batt]y1 he light$ ! auditorium ( ! ,royal ,in/itution ) ^! lamps dur+ "o ( ! lectures he gave4 ,?is lamp gave only a feeble light z !re 0 dang] ( melt+ ! plat9um & plat9um gives b little light unless op]at$ close to its melt+ temp]ature4 ,x also requir$ a lot ( curr5t to op]ate x z ! air t5d$ to cool ! inc&esc5t plat9um4 ,! demon/ration 0 only ( sci5tific int]e/1 ! co/ ( curr5t be+ mu* too great 7e/imat$ at sev]al hundr$ doll>s a kil[att h\r7 to make x comm]cial4 ,,gr5et ,,batt]y ,x 0 discov]$ t *romic anhydride gives up oxyg5 easi] ?an nitric acid & consequ5tly if us$ w\ld give a high] voltage ?an ,grove's nitric acid batt]y4 ,x also has ! advantage ( a less] t5d5cy to attack z9c directly if x happ5s to come 9 contact ) x4 ,gr5et develop$ a cell hav+ a liquid consi/+ ( a mixture ( potassium bi*romate 7,k#b;,cr#b,o#g7 & sulphuric acid4 ,a por\s cell 0 !re=e n us$ to keep ! two liquids ap>t4 ,?is _h ! advantage ( r$uc+ ! int]nal resi/ance4 ,! *emical reaction 03 ,k#b;,cr#b,o#g 7potassium bi*romate7 #g;,h#b,,s#d 7sulphuric acid7 #c,zn 7z9c7 #c,zn,s,o#d 7z9c sulphate7 ,k#b,,s#d 7potassium sulphate7 ,cr#b 7,,s#d7c 7*romium sulphate7 #g;,h#b,o 7wat]74 ,9 ord] to prev5t ! useless consumption ( z9c on op5 circuit1 ! z9c 0 atta*$ to a slid+ rod & c\ld be drawn up into ! neck ( ! bottle-%ap$ j> conta9+ ! liquid4 ,illu/ration3 ,,grove',s ,,inc&esc5t ,,lamp1 #ahdj4 ,grove made an exp]im5tal lamp1 us+ plat9um = ! burn] :i* 0 protect$ f draughts ( air by a glass tumbl]4 ,,de ,,moleyns' ,,inc&esc5t ,,lamp ,fr$]ick ,de ,moleyns1 an ,engli%man1 has ! honor ( hav+ obta9$ ! fir/ pat5t on an inc&esc5t lamp4 ,?is 0 9 #ahda & 8 lamp 0 q novel4 ,x consi/$ ( a sph]ical glass globe1 9 ! upp] "p ( :i* 0 a tube conta9+ p[d]$ *>coal4 ,?is tube 0 op5 at ! bottom inside ! globe & ?r\gh x ran a plat9um wire1 ! end bel[ ! tube be+ coil$4 ,ano!r plat9um wire coil$ at its upp] end came up ?r\gh ! l[] "p ( ! globe b did n q t\* ! o!r plat9um coil4 ,! p[d]$ *>coal fill$ ! two coils ( plat9um wire & bridg$ ! gap betwe54 ,curr5t pass+ ?r\gh ?is *>coal bridge heat$ x to inc&esc5ce4 ,! air 9 ! globe hav+ be5 remov$ z f> z 0 possible ) ! h& air pumps !n available1 ! *>coal did n imm$iately burn up1 ! small am\nt consum$ be+ replac$ by ! supply 9 ! tube4 ,! idea 0 +5i\s b ! lamp 0 impractical z ! globe rapidly black5$ f ! evaporation ( ! inc&esc5t *>coal4 ,illu/ration3 ,,de ,,moleyns' ,,inc&esc5t ,,lamp1 #ahda4 ,?is consi/$ ( two coils ( plat9um wire conta9+ p[d]$ *>coal op]at+ 9 a vacuum4 ,x is only ( int]e/ z ! fir/ inc&esc5t lamp on :i* a pat5t 7,briti%7 0 grant$4 ,,e>ly ,,developm5ts ,,( ,,! ,,arc ,,lamp ,x _h be5 f\nd t mo/ ( ! light ( ! arc came f ! tip ( ! positive electrode1 & t ! *>coal electrodes 7 rapidly consum$1 ! positive electrode ab\t twice z fa/ z ! negative4 ,me*anisms 7 design$ to take c>e ( ?is1 toge!r ) devices to />t ! arc by all[+ ! electrodes to t\* ea* o!r & !n pull+ !m ap>t ! prop] di/ance4 ,?is di/ance v>i$ f "o-eigh? to ?ree-qu>t]s ( an in*4 ,9 #ahdj ,buns51 ! ,g]man *emi/ :o inv5t$ ! buns5 burn]1 devis$ a process = mak+ h>d d5se c>bon p5cils :i* la/$ mu* long] ?an ! *>coal previ\sly us$4 ,! d5se c>bon f ! inside ( ! retorts ( gas mak+ plants 0 gr\nd up & mix$ ) molasses1 m\ld$ into %ape & bak$ at a high temp]ature4 ,buns5 also1 9 #ahdc1 *eap5$ ,grove's batt]y by sub/itut+ a h>d c>bon plate 9 place ( ! plat9um electrode4 ,illu/ration3 ,,wright',s ,,arc ,,lamp1 #ahde4 ,?is lamp is also only ( int]e/ z ! fir/ arc lamp on :i* a pat5t 7,briti%7 0 grant$4 ,f\r arcs play$ betwe5 ! five c>bon discs4 ,?omas ,wright1 an ,engli%man1 0 ! fir/ to pat5t an arc lamp4 ,?is 0 9 #ahde1 & ! lamp 0 a h& regulat$ device consi/+ ( five c>bon disks normally t\*+ ea* o!r & rotat$ by clockwork4 ,two ( ! disks c\ld be drawn outw>d by ?umb screws1 :i* 0 to be done aft] ! curr5t 0 turn$ on ?us e/abli%+ f\r arcs1 "o betwe5 ea* pair ( disks4 ,! next ye>1 #ahdf1 ,w4 ,e4 ,/aite1 ano!r ,engli%man1 made an arc lamp hav+ two v]tical c>bon p5cils4 ,! upp] 0 /ation>y4 ,! l[] 0 movable & actuat$ by clockwork direct$ by rat*ets :i* 9 turn 7 regulat$ by an electro-magnet controll$ by ! curr5t fl[+ ?r\gh ! arc4 ,?us ! l[] c>bon w\ld be mov$ up or d[n z requir$4 ,ar*]eau1 a ,fr5*man1 made a v simple arc lamp 9 #ahdh4 ,! upp] c>bon 0 fix$ & ! l[] "o 0 m\nt$ on a piece ( iron :i* c\ld be drawn d[n into a coil ( wire4 ,! weight ( ! l[] electrode 0 ov]balanc$ by a c\nt]weight1 s t :5 no curr5t 0 fl[+ ! two c>bons w\ld t\*4 ,:5 curr5t 0 turn$ on1 x fl[$ ?r\gh ! two c>bons & ?r\gh ! coil ( wire 7sol5oid7 :i* !n became en]giz$ & pull$ ! l[] c>bon d[n1 ?us /rik+ ! arc4 ,two ( ^! arc lamps 7 in/all$ 9 ,p>is & caus$ consid]able excitem5t4 ,aft] a few weeks ( unreliable op]ation1 x 0 f\nd t ! co/ ( curr5t f ! batt]ies 0 mu* too great to cont9ue _! use comm]cially4 ,! dynamo _h n progress$ f> en\gh to p]mit its use4 ,illu/ration3 ,,ar*]eau',s ,,arc ,,lamp1 #ahdh4 ,?is simple arc 0 controll$ by an electro-magnet1 & two lamps 7 in/all$ = /reet light+ 9 ,p>is1 curr5t be+ obta9$ f batt]ies4 ,,j\le',s ,,law ,j\le 0 an ,engli%man1 & 9 #ahdb began inve/igat+ ! relation betwe5 me*anical en]gy & heat4 ,he fir/ %[$ t1 by all[+ a weight to drop f a consid]able height & turn a paddle :eel 9 wat]1 ! temp]ature ( ! wat] w\ld increase 9 relation to ! "w done 9 turn+ ! :eel4 ,x is n[ kn[n t #ggh foot-p\nds 7#a lb4 fall+ #ggh feet1 #aj lbs4 fall+ #gg4h feet or #ggh lbs4 fall+ "o foot1 etc47 is ! me*anical equival5t ( en]gy equal to rais+ "o p\nd ( wat] "o degree ,fahr5heit4 ,! rate ( en]gy 7p[]7 is ! en]gy divid$ by a unit ( "t2 ?us "o horsep[] is #cc1jjj foot-p\nds p] m9ute4 ,j\le next inve/igat$ ! relation betwe5 heat & electric curr5t4 ,he made a device consi/+ ( a vessel ( wat] 9 :i* !re 7 a !rmomet] & an insulat$ coil ( wire hav+ a consid]able resi/ance4 ,he f\nd t an electric curr5t heat$ ! wat]1 & mak+ _m comb9ations ( ! am\nt & l5g? ( "t ( curr5t fl[+ & ( ! resi/ance ( ! wire1 he d$uc$ ! law t ! en]gy 9 an electric circuit is proportional to ! squ>e ( ! am\nt ( curr5t fl[+ multipli$ by ! l5g? ( "t & multipli$ by ! resi/ance ( ! wire4 ,! rate ( electrical en]gy 7electric p[]7 is !re=e proportional to ! squ>e ( curr5t multipli$ by ! resi/ance4 ,! electrical unit ( p[] is n[ call$ ! ,,watt1 nam$ 9 honor ( ,james ,watt1 ! ,engli%man1 :o made great improvem5ts to ! /eam eng9e ab\t a c5tury ago4 ,?us1 watts ,c#b,r & sub/itut+ ! value ( ,r f ,ohm's law1 ,c ,e_/,r1 we get ,watts ,volts ,amp]es ,! watt is a small unit ( electric p[]1 z c be se5 f ! fact t #gdf watts are equal to "o horsep[]4 ,! kil[att1 kilo be+ ! ,greek ^w = ?\s&1 is #ajjj watts4 ,?is t]m is an important "o 9 ! electrical indu/ry4 ,= example1 dynamos are rat$ 9 kil[atts1 express$ z ,,kw2 ! l>ge/ "o made s f> is #ej1jjj ,,kw :i* is #ff1fff horsep[]4 ,edison's fir/ comm]cial dynamo _h a capacity ( #f ,,kw al?\gh ! t]ms watts & kil[atts 7 n 9 use at t "t4 ,! ord9>y sizes ( inc&esc5t lamps n[ us$ 9 ! home are #be1 #dj & #ej watts4 ,,/>r',s ,,inc&esc5t ,,lamp ,illu/ration3 ,,/>r',s ,,inc&esc5t ,,lamp1 #ahde4 ,?is consi/$ ( a %ort c>bon p5cil op]at+ 9 ! vacuum above a column ( m]cury4 ,j4 ,w4 ,/>r1 an ,am]ican1 ( ,c9c9nati1 ,ohio1 assi/$ f9ancially by ,peabody1 ! philan?ropi/1 w5t to ,engl& :]e he obta9$ a pat5t 9 #ahde on ! lamps he _h inv5t$1 al?\gh ! pat5t 0 tak5 out "u ! "n ( ,k+1 8 attorney4 ,"o is ( pass+ int]e/ only4 ,x consi/$ ( a /rip ( plat9um1 ! active l5g? ( :i* c\ld be adju/$ to fit ! batt]y /r5g? us$1 & 0 cov]$ by a glass globe to protect x f draughts ( air4 ,! o!r1 a c>bon lamp1 0 ! fir/ real contribution to ! art4 ,x consi/$ ( a rod ( c>bon op]at+ 9 ! vacuum above a column ( m]cury 7,torrecellium vacuum7 z 9 a b>omet]4 ,a heavy plat9um wire 0 seal$ 9 ! upp] clos$ end ( a l>ge glass tube1 & connect$ to ! c>bon rod by an iron clamp4 ,! l[] end ( ! c>bon rod 0 fa/5$ to ano!r iron clamp1 ! two clamps be+ held 9 place & insulat$ f ea* o!r by a porcela9 rod4 ,atta*$ to ! l[] clamp 0 a long copp] wire4 ,j bel[ ! l[] clamp1 ! glass tube 0 n>r[$ d[n & _h a l5g? ( m ?an #cj in*es4 ,! tube 0 !n fill$ ) m]cury1 ! bottom ( ! tube be+ put into a vessel p>tly full ( m]cury4 ,! m]cury ran out ( ! enl>g$ upp] "p ( ! tube1 com+ to re/ 9 ! n>r[ "p ( ! tube z 9 a b>omet]1 s t ! c>bon rod 0 !n 9 a vacuum4 ,"o lamp t]m9al 0 ! plat9um wire ext5d+ ?r\gh ! top ( ! tube1 & ! o!r 0 ! m]cury4 ,sev]al ( ^! lamps 7 put on exhibition 9 ,london1 b 7 n a comm]cial success z !y black5$ v rapidly4 ,/>r />t$ 8 return trip to ! ,unit$ ,/ates ! next ye>1 b di$ on bo>d ! %ip :5 he 0 b #be ye>s old4 ,,o!r ,,e>ly ,,inc&esc5t ,,lamps ,illu/ration3 ,,/aite',s ,,inc&esc5t ,,lamp1 #ahdh4 ,! burn] 0 ( plat9um & iridium4 ,illu/ration3 ,,rob]ts' ,,inc&esc5t ,,lamp1 #aheb4 ,x _h a graphite burn] op]at+ 9 vacuum4 ,9 #ahdh ,w4 ,e4 ,/aite1 :o two ye>s previ\sly _h made an arc lamp1 inv5t$ an inc&esc5t lamp4 ,?is consi/$ ( a plat9um-iridium burn] 9 ! %ape ( an inv]t$ ,u1 cov]$ by a glass globe4 ,x _h a ?umb screw = a swit*1 ! :ole device be+ m\nt$ on a bracket :i* 0 us$ = ! return wire4 ,e4 ,c4 ,%ep>d1 ano!r ,engli%man1 obta9$ a pat5t two ye>s lat] on an inc&esc5t lamp consi/+ ( a weight$ holl[ *>coal cyl9d] ! end ( :i* press$ aga9/ a *>coal cone4 ,curr5t pass+ ?r\gh ?is high resi/ance contact1 heat$ ! *>coal to inc&esc5ce4 ,x op]at$ 9 a glass globe f :i* ! air c\ld be exhau/$4 ,m4 ,j4 ,rob]ts obta9$ an ,engli% pat5t 9 #aheb on an inc&esc5t lamp4 ,?is _h a graphite rod = a burn]1 :i* c\ld be r5ew$1 m\nt$ 9 a glass globe4 ,! globe 0 cem5t$ to a metallic cap fa/5$ to a piece ( pipe ?r\gh :i* ! air c\ld be exhau/$4 ,aft] be+ exhau/$1 ! pipe1 hav+ a /op cock1 c\ld be screw$ on a /& to support ! lamp4 ,moses ,g4 ,f>m]1 a pr(essor at ! ,naval ,tra9+ ,/ation at ,newport1 ,rhode ,isl&1 light$ ! p>lor ( 8 home at #aa ,pe>l ,/reet1 ,salem1 ,mass41 dur+ ,july1 #ahei1 ) sev]al inc&esc5t lamps hav+ a /rip ( plat9um = ! burn]4 ,! novel feature ( ?is lamp 0 t ! plat9um /rip 0 n>r[] at ! t]m9als ?an 9 ! c5t]4 ,heat is conduct$ away f ! t]m9als & by mak+ ! burn] ?9 at ^! po9ts1 ! great] resi/ance ( ! ends ( ! burn] absorb$ m electrical en]gy ?us (fsett+ ! heat be+ conduct$ away4 ,?is made a m uni=m degree ( inc&esc5ce ?r\gh\t ! l5g? ( ! burn]1 & ,pr(4 ,f>m] obta9$ a pat5t on ?is pr9ciple _m ye>s lat] 7#ahhb74 ,illu/ration3 ,,f>m]',s ,,inc&esc5t ,,lamp1 #ahei4 ,?is exp]im5tal plat9um lamp 0 made by ,pr(essor ,f>m] & sev]al ( !m light$ ! p>lor ( 8 home 9 ,salem1 ,mass4 ,,fur!r ,,arc ,,lamp ,,developm5ts ,dur+ ! t5 ye>s1 #ahej to #ahfj1 sev]al inv5tors develop$ arc lamp me*anisms4 ,among !m 0 ,m4 ,j4 ,rob]ts1 :o _h inv5t$ ! graphite inc&esc5t lamp4 ,9 ,rob]ts' arc lamp1 :i* he pat5t$ 9 #aheb1 ! l[] c>bon 0 /ation>y4 ,! upp] c>bon fitt$ snugly into an iron tube4 ,9 ! tube 0 a brass cov]$ iron rod1 :i* by its weight c\ld pu% ! upp] c>bon d[n ! tube s ! two c>bons normally 7 9 contact4 ,an electro-magnet 9 s]ies ) ! arc 0 s locat$ t1 :5 en]giz$1 x pull$ up ! iron tube4 ,?is magnet also held ! brass cov]$ iron rod f pu%+ ! upp] c>bon d[n ! tube s t ! two c>bons 7 pull$ ap>t1 /rik+ ! arc4 ,:5 ! arc w5t out1 ! iron tube dropp$ back into its orig9al position1 ! brass cov]$ iron rod 0 releas$1 pu%+ ! upp] c>bon d[n ! tube until ! two c>bons aga9 t\*$4 ,?is clos$ ! circuit aga91 /rik+ ! arc z be=e4 ,illu/ration3 ,,rob]ts' ,,arc ,,lamp1 #aheb4 ,! arc 0 controll$ by an electro-magnet :i* held an iron tube to :i* ! upp] c>bon 0 fa/5$4 ,illu/ration3 ,,slat] ,,& ,,watson',s ,,arc ,,lamp1 #aheb4 ,clut*es 7 us$ = ! fir/ "t 9 ?is arc lamp to fe$ ! c>bons4 ,9 ! same ye> 7#aheb7 ,slat] & ,watson obta9$ an ,engli% pat5t on an arc lamp 9 :i* ! upp] c>bon 0 movable & held 9 place by two clut*es actuat$ by electro-magnets4 ,! l[] c>bon 0 fix$1 & normally ! two c>bons t\*$ ea* o!r4 ,:5 curr5t 0 turn$ on1 ! electro-magnet lift$ ! clut*es :i* gripp$ ! upp] c>bon1 pull+ x up & /rik+ ! arc4 ,?is 0 ! fir/ "t t a clut* 0 us$ to all[ ! c>bon to fe$ z x became consum$4 ,h5ry ,*apman1 9 #ahee1 made an arc 9 :i* ! upp] c>bon 0 all[$ to fe$ by gravity1 b held 9 place by a *a9 w\nd ar\nd a :eel4 ,on ?is :eel 0 a brake actuat$ by an electro-magnet4 ,! l[] c>bon 0 pull$ d[n by an electro-magnet work+ aga9/ a spr+4 ,:5 no curr5t 0 fl[+ or :5 ! arc w5t out1 ! two c>bons t\*$4 ,) curr5t on1 "o electro-magnet set ! brake & held ! upp] c>bon /ation>y4 ,! o!r electro-magnet pull$ ! l[] c>bon d[n1 ?us /rik+ ! arc4 ,none ( ^! me*anisms regulat$ ! l5g? ( ! arc4 ,x 0 n until #ahef t ,joseph ,lacassagne & ,h5ry ,?i]s1 ,fr5*m51 inv5t$ ! s-call$ 8diff]5tial0 me?od ( control1 :i* made ! c>bons fe$ :5 ! arc voltage1 & h5ce l5g?1 became too great4 ,?is pr9ciple 0 us$ 9 comm]cial arc lamps sev]al ye>s aft]w>d :5 !y 7 op]at$ on s]ies circuits1 z x _h ! add$ advantage ( prev5t+ ! fe$+ ( "o arc lamp affect+ ano!r on ! same circuit4 ,?is diff]5tial control consi/s 9 pr9ciple ( two electro-magnets1 "o 9 s]ies )1 & oppos+ ! pull ( ! o!r :i* is 9 %unt ) ! arc4 ,! s]ies magnet pulls ! c>bons ap>t & /rikes ! arc4 ,z ! arc increases 9 l5g?1 its voltage rises1 !reby increas+ ! curr5t fl[+ ?r\gh ! %unt magnet4 ,?is increases ! /r5g? ( ! %unt magnet &1 :5 ! arc becomes too long1 ! /r5g? ( ! %unt becomes great] ?an t ( ! s]ies magnet1 ?us mak+ ! c>bons fe$4 ,illu/ration3 ,,diagram ,,( 8,,diff]5tial0 ,,me?od ,,( ,,control ,,( ,,an ,,arc ,,lamp4 ,?is pr9ciple1 inv5t$ by ,lacassagne & ,?i]s1 0 us$ 9 all arc lamps :5 !y 7 comm]cially introduc$ on a l>ge scale m ?an tw5ty ye>s lat]4 ,! actual me?od adopt$ by ,lacassagne & ,?i]s 0 diff]5t f ?is1 b x _h ?is pr9ciple4 ,!y us$ a column ( m]cury on :i* ! l[] c>bon float$4 ,! upp] c>bon 0 /ation>y4 ,! height ( ! m]cury column 0 regulat$ by a valve connect$ ) a res]voir ( m]cury4 ,! pull ( ! s]ies magnet clos$ ! valve fix+ ! height ( ! column4 ,! pull ( ! %unt magnet t5d$ to op5 ! valve1 & :5 x ov]came ! pull ( ! s]ies magnet x all[$ m]cury to fl[ f ! res]voir1 rais+ ! height ( ! column br++ ! c>bons ne>] toge!r4 ,?is r$uc$ ! arc voltage & %unt magnet /r5g? until ! valve clos$ aga94 ,?us ! c>bons 7 always kept ! prop] di/ance ap>t4 ,9 fir/ />t+ ! arc1 or if ! arc %\ld g out1 curr5t w\ld only fl[ ?r\gh ! %unt magnet1 br++ ! two c>bons toge!r until !y t\*$4 ,curr5t w\ld !n fl[ ?r\gh ! contact ( ! two c>bons & ?r\gh ! s]ies magnet1 %utt+ ! valve4 ,!re 7 no means ( pull+ ! c>bons ap>t to /rike ! arc4 ,curr5t fl[+ ?r\gh ! high resi/ance ( ! poor contact ( ! two c>bons1 heat$ _! tips to inc&esc5ce4 ,! inc&esc5t tips w\ld beg9 to burn away1 ?us aft] a "t />t+ an arc4 ,! arc1 h[ev]1 once />t$ 0 ma9ta9$ ! prop] l5g?4 ,illu/ration3 ,,lacassagne ,,& ,,?i]s' ,,diff]5tially ,,controll$ ,,arc ,,lamp1 #ahef4 ,! l[] c>bon float$ on a column ( m]cury ^: height 0 8diff]5tially0 controll$ by s]ies & %unt magnets4 ,9 #aheg1 ,s]r9 took out 8 fir/ pat5t on an arc lamp1 ! g5]al pr9ciples ( :i* 7 ! same z 9 o!rs he made4 ,! me*anism consi/$ ( two drums1 "o d\ble ! diamet] ( ! o!r4 ,bo? c>bons 7 movable1 ! upp] "o fe$+ d[n1 & ! l[] "o fe$+ up1 be+ connect$ ) *a9s w\nd ar\nd ! drums4 ,! diff]5ce 9 consumption ( ! two c>bons 0 !re=e comp5sat$ = by ! diff]5ce 9 size ( ! drums1 ?us ma9ta9+ ! location ( ! arc 9 a fix$ position4 ,a tra9 ( :eels controll$ by a pawl & regulat$ by an electro-magnet1 controll$ ! movem5t ( ! c>bons4 ,! weight ( ! upp] c>bon & its hold] actuates ! tra9 ( :eels4 ,illu/ration3 ,,s]r9',s ,,arc ,,lamp1 #aheg4 ,?is type ( arc 0 n diff]5tially controll$ b 0 ! fir/ comm]cial lamp lat] us$4 ,bo? c>bons 7 movable1 held by *a9s w\nd ar\nd drums :i* 7 controll$ by rat*ets actuat$ by an electro-magnet4 ,,developm5t ,,( ,,! ,,dynamo1 #ahdj-ahfj ,dur+ ! fir/ few ye>s aft] #ahdj ! dynamo 0 only a laboratory exp]im5t4 ,woolri* devis$ a ma*9e :i* _h sev]al pairs ( magnets & d\ble ! numb] ( coils 9 ord] to make ! curr5t obta9$ less pulsat+4 ,:eat/one 9 #ahde pat5t$ ! use ( electro-magnets 9 place ( p]man5t magnets4 ,brett 9 #ahdh sugge/$ t ! curr5t1 g5]at$ 9 ! coils1 be all[$ to fl[ ?r\gh a coil surr\nd+ ea* p]man5t magnet to fur!r /r5g!n ! magnets4 ,pulv]ma*] 9 #ahdi propos$ ! use ( ?9 plates ( iron = ! bobb9s1 to r$uce ! eddy curr5ts g5]at$ 9 ! iron4 ,s9/$5 9 #ahea sugge/$ t ! curr5t f a p]man5t magnet ma*9e be us$ to excite ! field coils ( an electro-magnet ma*9e4 ,9 #ahee ,sor5 ,hjor?1 ( ,cop5hag51 ,d5m>k1 pat5t$ a dynamo hav+ bo? p]man5t & electro-magnets1 ! latt] be+ excit$ by curr5ts fir/ induc$ 9 ! bobb9s by ! p]man5t magnets4 ,9 #ahef ,dr4 ,w]n] ,siem5s inv5t$ ! %uttle w\nd armature4 ,?is consi/$ ( a s+le coil ( wire w\nd l5g?wise & c\nt] sunk 9 a long cyl9drical piece ( iron4 ,?is revolv$ betwe5 ! magnet poles :i* 7 %ap$ to fit ! cyl9drical armature4 ,illu/ration3 ,,siem5s' ,,dynamo1 #ahef4 ,?is dynamo 0 an improvem5t ov] o!rs on acc\nt ( ! con/ruction ( its 8%uttle0 armature4 ,,! ,,fir/ ,,comm]cial ,,in/allation ,,( ,,an ,,electric ,,light ,9 #ahfb a ,s]r9 type ( arc lamp 0 in/all$ 9 ! ,dung5ess ligh?\se 9 ,engl&4 ,curr5t 0 suppli$ by a dynamo made by ! ,alliance ,company1 :i* _h be5 orig9ally design$ 9 #ahej by ,nollet1 a pr(essor ( ,physics 9 ! ,milit>y ,s*ool 9 ,brussels4 ,nollet's orig9al design 0 ( a dynamo hav+ sev]al r[s ( p]man5t magnets m\nt$ radially on a /ation>y frame1 ) an equal numb] ( bobb9s m\nt$ on a %aft :i* rotat$ & _h a commutator s direct curr5t c\ld be obta9$4 ,a company 0 =m$ to sell hydrog5 gas = illum9at+ purposes1 ! gas to be made by ! decomposition ( wat] ) curr5t f ?is ma*9e4 ,nollet di$ & ! company fail$1 b x 0 reorganiz$ z ! ,alliance ,company a few ye>s lat] to exploit ! arc lamp4 ,illu/ration3 ,,alliance ,,dynamo1 #ahfb4 ,?is 0 ! dynamo us$ 9 ! fir/ comm]cial in/allation ( an arc light 9 ! ,dung5ess ,ligh?\se1 ,engl&1 #ahfb4 ,ab\t ! only *ange made 9 ! dynamo 0 to sub/itute collector r+s = ! commutator to ov]come ! difficulties ( commutation4 ,alt]nat+ curr5t 0 !re=e g5]at$ 9 ?is fir/ comm]cial ma*9e4 ,x _h a capacity = b "o arc light1 :i* probably consum$ less ?an t5 amp]es at ab\t #de volts1 h5ce deliv]$ 9 ! pres5t t]m9ology n ov] #dej watts or ab\t two-?irds ( a horsep[]4 ,z ! bobb9s ( ! armature und\bt$ly _h a consid]able resi/ance1 ! ma*9e _h an effici5cy ( n ov] #ej p] c5t & !re=e requir$ at lea/ "o & a qu>t] horsep[] to drive x4 ,,fur!r ,,dynamo ,,developm5ts ,9 ! summ] ( #ahhf ,sir ,*>les ,:eat/one con/ruct$ a self-excit$ ma*9e on ! pr9ciple ( us+ ! residual magnetism 9 ! field poles to set up a feeble curr5t 9 ! armature :i*1 pass+ ?r\gh ! field coils1 gradually /r5g!n$ ! fields until !y built up to normal /r5g?4 ,x 0 lat] f\nd t ?is idea _h be5 ?\ght ( by an unkn[n man1 be+ disclos$ by a clause 9 a provisional #aheh ,engli% pat5t tak5 out by 8 ag5t4 ,:eat/one's ma*9e 0 %[n to ! ,royal ,society 9 ,london & a pap] on x read be=e ! ,society on ,febru>y #ad1 #ahfg4 ,! field coils 7 %unt w\nd4 ,illu/ration3 ,,:eat/one',s ,,self-,,excit$ ,,dynamo1 #ahff4 ,?is ma*9e 0 ! fir/ self-excit$ dynamo by use ( ! residual magnetism 9 ! field poles4 ,dr4 ,w]n] ,siem5s also made a self-excit$ ma*9e1 hav+ s]ies fields1 a pap] on :i* 0 read be=e ! ,academy ( ,sci5ces 9 ,b]l9 on ,janu>y #ag1 #ahfg4 ,?is pap] 0 =w>d$ to ! ,royal ,society 9 ,london & pres5t$ at ! same meet+ at :i* ,:eat/one's dynamo 0 describ$4 ,:eat/one probably prec$$ ,siem5s 9 ?is re-discov]y ( ! pr9ciple ( self-excitation1 b bo? are giv5 ! m]it ( x4 ,h[ev]1 ,s4 ,a4 ,v>ley on ,decemb] #bd1 #ahff1 obta9$ a provisional ,engli% pat5t on ?is1 :i* 0 n publi%$ until ,july1 #ahfg4 ,illu/ration3 ,,gramme',s ,,dynamo1 #ahga4 ,^! 7 comm]cially us$1 _! ma9 feature be+ ! 8r+0 w\nd armature4 ,illu/ration3 ,,gramme',s 8,,r+0 ,,armature4 ,wire coils1 surr\nd+ an iron wire core1 7 all connect$ toge!r 9 an endless r+1 ea* coil be+ tapp$ ) a wire connect$ to a commutator b>4 ,9 #ahgj ,gramme1 a ,fr5*man1 pat5t$ 8 well-kn[n r+ armature4 ,! idea _h be5 previ\sly ?\ght ( by ,elias1 a ,holl&]1 9 #ahdb1 & by ,pac9notti1 an ,italian1 z %[n by ! crude motors 7n dynamos7 !y _h made4 ,gramme's armature consi/$ ( an iron wire core coat$ ) a bitum9\s comp\nd 9 ord] to r$uce ! eddy curr5ts4 ,?is core 0 w\nd ) insulat$ wire coils1 all connect$ toge!r 9 s]ies z "o s+le endless coil4 ,ea* coil 0 tapp$ ) a wire connect$ to a commutator b>4 ,8 fir/ ma*9e1 hav+ p]man5t magnets = fields1 0 submitt$ to ! ,fr5* ,academy ( ,sci5ces 9 #ahga4 ,lat] ma*9es 7 made ) self-excit$ field coils1 :i* 7 us$ 9 comm]cial s]vice4 ,!y _h1 h[ev] a high resi/ance armature1 s t _! effici5cy did n exce$ #ej p] c5t4 ,illu/ration3 ,,alt5eck',s ,,dynamo ,,) 8,,drum0 ,,w\nd ,,armature1 #ahgb4 ,! armature w9d+ 0 entirely on ! surface ( ! armature core1 a pr9ciple n[ us$ 9 all dynamos4 ,von ,hefn] ,alt5eck1 an eng9e] ) ,siem5s1 inv5t$ ! drum w\nd armature 9 #ahgb4 ,! wires ( ! armature 7 all on ! surface ( ! armature core1 ! wires be+ tapp$ at frequ5t po9ts = connection ) ! commutator b>s4 ,?us 9 ! e>ly sev5ties1 comm]cial dynamos 7 available = use 9 arc light+1 & a few in/allations 7 made 9 ,europe4 ,,russian ,,inc&esc5t ,,lamp ,,inv5tors ,9 #ahgb ,lodygu9e1 a ,russian sci5ti/1 made an inc&esc5t lamp consi/+ ( a 8,v0 %ap$ piece ( graphite = a burn]1 :i* op]at$ 9 nitrog5 gas4 ,he light$ ! ,admiralty ,docky>d at ,/4 ,pet]sburg ) ab\t two hundr$ ( ^! lamps4 ,9 #ahgb ! ,russian ,academy ( ,sci5ces aw>d$ him a prize ( #ej1jjj rubles 7a lot ( real money at t "t7 = 8 inv5tion4 ,a company ) a capital ( #bjj1jjj rubles 7!n equal to ab\t #ajj1jjj7 0 =m$ b z ! lamp 0 s exp5sive to op]ate & _h su* a %ort life1 ab\t twelve h\rs1 ! project fail$4 ,illu/ration3 ,,lodygu9e',s ,,inc&esc5t ,,lamp1 #ahgb4 ,! burn] 0 made ( graphite & op]at$ 9 nitrog5 gas4 ,illu/ration3 ,,konn',s ,,inc&esc5t ,,lamp1 #ahge4 ,9 ?is lamp ! graphite rods op]at$ 9 a vacuum4 ,kosl(f1 ano!r ,russian1 9 #ahge pat5t$ a graphite 9 nitrog5 inc&esc5t lamp1 :i* _h sev]al graphite rods = burn]s1 s arrang$ t :5 "o fail$ ano!r 0 automatically connect$4 ,konn1 also a ,russian1 made a lamp simil> to ,kosl(f's except t ! graphite rods op]at$ 9 a vacuum4 ,b\ligu9e1 ano!r ,russian1 9 #ahgf made an inc&esc5t lamp hav+ a long graphite rod1 only ! upp] "p ( :i* 0 9 circuit4 ,z ?is "p burn$ out1 ! rod 0 automatically pu%$ up s t a fre% portion !n 0 9 circuit4 ,x op]at$ 9 a vacuum4 ,none ( ^! lamps 0 comm]cial z !y black5$ rapidly & 7 too exp5sive to ma9ta94 ,illu/ration3 ,,b\ligu9e',s ,,inc&esc5t ,,lamp1 #ahgf4 ,a long graphite rod1 ! upp] "p ( :i* only 0 9 circuit1 op]at$ 9 vacuum4 ,z ?is "p burn$ out1 ! rod 0 automatically %ov$ up1 a fre% portion !n be+ 9 ! circuit4 ,,! ,,jablo*k(f 8,,c&le0 ,paul ,jablo*k(f 0 a ,russian army (fic] & an eng9e]4 ,9 ! e>ly sev5ties he came to ,p>is & develop$ a novel arc light4 ,?is consi/$ ( a pair ( c>bons held toge!r side by side & insulat$ f ea* o!r by a m9]al kn[n z kaol9 :i* vaporiz$ z ! c>bons 7 consum$4 ,!re 0 no me*anism1 ! arc be+ />t$ by a ?9 piece ( c>bon across ! tips ( ! c>bons4 ,curr5t burn$ ?is bridge1 />t+ ! arc4 ,! e>ly c>bons 7 ab\t five in*es long1 & ! positive c>bon 0 twice z ?ick z ! negative to comp5sate = ! unequal consumption on direct curr5t4 ,?is1 h[ev]1 did n "w satisfactorily4 ,lat] ! l5g? ( ! c>bons 0 increas$1 ! c>bon made ( equal ?ickness & burn$ on alt]nat+ curr5t ( ab\t eight or n9e amp]es at ab\t #de volts4 ,he made an alt]nat+ curr5t g5]ator :i* _h a /ation>y ext]ior armature ) int]ior revolv+ field poles4 ,sev]al 8c&les10 z !y 7 call$1 7 put 9 "o fixture to p]mit all night s]vice & an automatic device 0 develop$1 locat$ 9 ea* fixture1 s t %\ld "o 8c&le0 g out = any reason1 ano!r 0 swit*$ into s]vice4 ,illu/ration3 ,,jablo*k(f 8,,c&le10 #ahgf4 ,?is simple arc consi/$ ( a pair ( c>bons held toge!r side by side & insulat$ f ea* o!r by kaol94 ,sev]al b\lev>ds 9 ,p>is 7 light$ ) ^! arc lights4 ,?is arc lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,9 #ahgf _m ( ^! 8c&les0 7 in/all$ & lat] sev]al ( ! b\lev>ds 9 ,p>is 7 light$ ) !m4 ,?is 0 ! fir/ l>ge in/allation ( ! arc light1 & 0 ! beg9n+ ( its comm]cial introduction4 ,h5ry ,wilde made "s improvem5ts 9 ! c&le by elim9at+ ! kaol9 betwe5 ! c>bons :i* gave ,jablo*k(f's arc its peculi> color4 ,wilde's arc 0 />t$ by all[+ ! ends ( ! c>bons to t\* ea* o!r1 a magnet sw++ !m ap>t ?us /rik+ ! arc4 ,illu/ration3 ,,jablo*k(f',s ,,alt]nat+ ,,curr5t ,,dynamo1 #ahgf4 ,?is dynamo _h a /ation>y ext]ior armature & int]nal revolv+ field poles4 ,alt]nat+ curr5t 0 us$ = ! ,jablo*k(f 8c&le0 to ov]come ! difficulties ( unequal consumption ( ! c>bons on direct curr5t4 ,,comm]cial ,,introduction ,,( ,,! ,,diff]5tially ,,controll$ ,,arc ,,lamp ,ab\t ! same "t ,lont91 a ,fr5*man1 improv$ ,s]r9's arc lamp me*anism by ! application ( s]ies & %unt magnets4 ,?is is ! diff]5tial pr9ciple :i* 0 inv5t$ by ,lacassagne & ,?i]s 9 #ahee b :i* app>5tly _h be5 =gott54 ,sev]al ( ^! lamps 7 comm]cially in/all$ 9 ,france beg9n+ ) #ahgf4 ,,arc ,,light+ ,,9 ,,! ,,unit$ ,,/ates ,illu/ration3 ,,wallace-,,f>m] ,,arc ,,lamp1 #ahge4 ,?is 8diff]5tially controll$0 arc lamp consi/$ ( two slabs ( c>bon betwe5 :i* ! arc play$4 ,9 ! orig9al lamp ! c>bon slabs 7 m\nt$ on pieces ( wood held 9 place by bolts1 adju/m5t be+ made by hitt+ ! upp] c>bon slab ) a hamm]4 ,?is lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,illu/ration3 ,,wallace-,,f>m] ,,dynamo1 #ahge4 ,?is 0 ! fir/ comm]cial dynamo us$ 9 ! ,unit$ ,/ates = arc light+4 ,?is dynamo is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,ab\t #ahge ,william ,wallace ( ,ansonia1 ,connecticut1 made an arc light consi/+ ( two rectangul> c>bon plates m\nt$ on a wood5 frame4 ,! arc play$ betwe5 ! two edges ( ! plates1 :i* la/$ mu* long] ?an rods4 ,:5 ! edges _h burn$ away s t ! arc !n became unduly long1 ! c>bon plates 7 br\ght clos] toge!r by hitt+ !m ) a hamm]4 ,wallace became associat$ ) ,moses ,g4 ,f>m]1 & !y improv$ ?is crude arc by fa/5+ ! upp] c>bon plate to a rod :i* 0 held by a clut* controll$ by a magnet4 ,?is magnet _h two coils 9 "o1 ! inn] w9d+ 9 s]ies ) ! arc1 & out] "o 9 %unt & oppos+ ! s]ies w9d+4 ,! arc 0 !re=e diff]5tially controll$4 ,illu/ration3 ,,we/on',s ,,arc ,,lamp1 #ahgf4 ,?is lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,!y also develop$ a s]ies w\nd direct curr5t dynamo4 ,! armature consi/$ ( a numb] ( bobb9s1 all connect$ toge!r 9 an endless r+4 ,ea* bobb9 0 also connect$ to a commutator b>4 ,!re 7 two sets ( bobb9s1 commutators & field poles1 ! equival5t ( two ma*9es 9 "o1 :i* c\ld be connect$ ei!r to sep>ate circuits1 or toge!r 9 s]ies on "o circuit4 ,! ,wallace-,f>m] sy/em 0 comm]cially us$4 ,! arc consum$ ab\t #bj amp]es at ab\t #ce volts1 b z ! c>bon plates cool$ ! arc1 ! effici5cy 0 poor4 ,! arc flick]$ back & =? on ! edges ( ! c>bons ca/+ danc+ %ad[s4 ,! c>bons1 :ile la/+ ab\t #ej h\rs1 7 n uni=m 9 d5sity1 s ! arc w\ld fl>e up & ca/ (f soot & sp>ks4 ,edw>d ,we/on ( ,new>k1 ,new ,j]sey1 also develop$ an arc light+ sy/em4 ,8 comm]cial lamp _h c>bon rods1 "o above ! o!r1 & ! arc 0 also diff]5tially controll$4 ,an oil da% pot prev5t$ undue pump+ ( ! c>bons4 ,8 dynamo _h a drum-w\nd armature1 & _h sev]al horizontal field coils on ea* side ( "o pair ( poles betwe5 :i* ! armature revolv$4 ,! sy/em 0 design$ = ab\t #bj amp]es1 ea* are tak+ ab\t #ce volts4 ,illu/ration3 ,,bru%',s ,,dynamo1 #ahgg4 ,?is dynamo 0 us$ = _m ye>s = comm]cial arc light+4 ,illu/ration3 ,,diagram ,,( ,,bru% ,,armature4 ,! armature 0 n a clos$ circuit4 ,= description ( its op]ation1 see text4 ,*>les ,f4 ,bru% made a v successful arc light+ sy/em 9 #ahgh4 ,8 dynamo 0 unique 9 t ! armature _h eight coils1 "o end ( ea* pair ( opposite coils be+ connect$ toge!r & ! o!r ends connect$ to a commutator segm5t4 ,?us ! armature itself 0 n a clos$ circuit4 ,! ma*9e _h two pairs ( horizontal poles betwe5 :i* ! coils revolv$4 ,"o end ( ! "o pair ( coils 9 ! mo/ active position 0 connect$1 by means ( two ( ! f\r bru%es1 9 s]ies ) "o end ( ! two pairs ( coils 9 ! less] active position4 ,! latt] two pairs ( coils 7 connect$ 9 multiple ) ea* o!r by means ( ! bru%es t\*+ adjac5t commutator segm5ts4 ,! outside circuit 0 connect$ to ! o!r two bru%es1 "o ( :i* 0 connect$ to ! o!r end ( ! mo/ active pair ( coils4 ,! o!r bru% 0 connect$ to ! o!r end ( ! two less] active pairs ( coils4 ,! "o pair ( coils 9 ! lea/ active position 0 out ( circuit4 ,! field coils 7 connect$ 9 s]ies ) ! outside circuit4 ,illu/ration3 ,,bru%',s ,,arc ,,lamp1 #ahgg4 ,! c>bons 7 diff]5tially controll$4 ,?is lamp 0 us$ = _m ye>s4 ,?is lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,bru%'s arc lamp 0 also diff]5tially controll$4 ,x 0 design$ = ab\t #aj amp]es at ab\t #de volts4 ,! c>bons 7 copp] plat$ to increase _! conductivity4 ,two pairs ( c>bons 7 us$ = all-night s]vice1 ea* pair la/+ ab\t eight h\rs4 ,a v simple device 0 us$ to automatically swit* ! arc f "o to ! o!r pair ( c>bons1 :5 ! fir/ pair 0 consum$4 ,?is device consi/$ ( a triangul>-%ap$ piece ( iron connect$ to ! sol5oid controll+ ! arc4 ,!re 0 a groove on ea* ( ! out] two corn]s ( ?is triangle1 "o groove wid] ?an ! o!r4 ,an iron wa%] surr\nd$ ea* upp] c>bon4 ,! edge ( ea* wa%] re/$ 9 a groove4 ,! wa%] 9 ! n>r[ groove made a comp>atively tight fit ab\t its c>bon4 ,! o!r wa%] 9 ! wid] groove _h a loose fit ab\t its c>bon4 ,p9s prev5t$ ! wa%] f fall+ bel[ giv5 po9ts4 ,bo? pairs ( c>bons t\*$ ea* o!r at ! />t4 ,:5 curr5t 0 turn$ on1 ! sol5oid lift$ ! triangle1 ! loose-fitt+ wa%] gripp$ its c>bon fir/1 s t curr5t !n only pass$ ?r\gh ! o!r pair ( c>bons :i* 7 /ill t\*+ ea* o!r4 ,! fur!r movem5t ( ! sol5oid !n sep>at$ ^! c>bons1 ! arc />t+ betwe5 !m4 ,:5 ?is pair ( c>bons became consum$1 !y c\ld n fe$ any m s t ! sol5oid w\ld !n all[ ! o!r pair ( c>bons to t\*1 transf]r+ ! arc to t pair4 ,illu/ration3 ,,?omson-,,h\/on ,,arc ,,dynamo1 #ahgh4 ,?is dynamo 0 /&>d = _m ye>s4 ,?is ma*9e is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,elihu ,?omson & ,edw9 ,j4 ,h\/on 9 #ahgh made a v successful & complete arc light sy/em4 ,_! dynamo 0 specially design$ to fit ! requirem5ts ( ! s]ies arc lamp4 ,! ,?omson-,h\/on ma*9e 0 a bipol>1 hav+ an armature consi/+ ( ?ree coils1 "o end ( ea* ( ! ?ree coils hav+ a common t]m9al1 or 8,y0 connect$1 z x is call$4 ,! o!r end ( ea* coil 0 connect$ to a commutator segm5t4 ,! ma*9e 0 to a great ext5t self-regulat+1 t is ! curr5t 0 inh]5tly con/ant ) fluctuat+ load1 z occurs :5 ! lamps fe$ or :5 ! numb] ( lamps burn+ at "o "t %\ld *ange = any reason4 ,?is regulation 0 accompli%$ by :at is call$ 8armature reaction10 :i* is ! effect ! magnetization ( ! armature has on ! field /r5g?4 ,close regulation 0 obta9$ by a sep>ate electro-magnet1 9 s]ies ) ! circuit1 :i* %ift$ ! bru%es z ! load *ang$4 ,z !re 7 b ?ree commutator segm5ts1 "o = ea* coil1 excessive sp>k+ 0 prev5t$ by an air bla/4 ,illu/ration3 ,,diagram ,,( ,t-,h ,,arc ,,light+ ,,sy/em4 ,! 8,t-,h0 7,?ompson-,h\/on7 lamp employ$ ! %unt fe$ pr9ciple4 ,! c>bons 7 normally sep>at$1 be+ 9 mo/ types drawn ap>t by a spr+4 ,a high resi/ance magnet1 %unt$ ar\nd ! arc1 s]v$ to draw ! c>bons toge!r4 ,?is occurr$ on />t+ ! lamp & !reaft] ! voltage ( ! arc 0 held con/ant by ! balance betwe5 ! spr+ & ! %unt magnet4 ,z ! c>bon burn$ away ! me*anism advanc$ to a po9t :]e a clut* 0 tripp$1 ! c>bons br\ght toge!r1 & ! cycle repeat$4 ,bo? ! ,t-,h & ,bru% sy/ems 7 ext5sively us$ 9 /reet light+1 = :i* !y 7 ! /&>d :5 ! op5 arc 0 sup]s$$ by ! enclos$4 ,,o!r ,,am]ican ,,arc ,,light ,,sy/ems ,illu/ration3 ,,?omson-,,h\/on ,,arc ,,lamp1 #ahgh4 ,?is is an e>ly model ) a s+le pair ( c>bons4 ,illu/ration3 ,,?omson ,,d\ble ,,c>bon ,,arc ,,lamp4 ,?is lat] model1 hav+ two pairs ( c>bons1 0 comm]cially us$ = _m ye>s4 ,?is lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,beg9n+ ) ab\t #ahhj1 sev]al arc light sy/ems 7 develop$4 ,among ^! 7 ! ,v&]poele1 ,ho*aus51 ,wat]h\se1 ,maxim1 ,s*uyl] & ,wood4 ,! direct curr5t c>bon arc is inh]5tly m effici5t ?an ! alt]nat+ curr5t lamp1 ow+ to ! fact t ! cont9u\s fl[ ( curr5t 9 "o direction ma9ta9s on ! positive c>bon a l>g] crat] at ! vaporiz+ po9t ( c>bon4 ,?is s\rce furni%es ! l>ge/ proportion ( light1 ! small] crat] 9 ! negative c>bon mu* less4 ,) ! alt]nat+ curr5t arc1 ! l>ge crat] is =m$ fir/ on ! upp] & !n on ! l[] c>bon4 ,on acc\nt ( ! cool+ betwe5 alt]nations1 ! mean temp]ature falls bel[ ! vaporiz+ po9t ( c>bon1 ?us acc\nt+ = ! l[] effici5cy ( ! alt]nat+ curr5t arc4 ,illu/ration3 ,,maxim ,,dynamo4 ,?is dynamo is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,= ?is reason all ^! sy/ems us$ direct curr5t & ! #aj amp]e ultimately displac$ ! #bj amp]e sy/em4 ,! #aj amp]e circuit 0 lat] /&>diz$ at #i4f amp]es1 #ej volts p] lamp4 ,! lamp !re=e consum$ #dhj watts giv+ an effici5cy ( ab\t #ae lum5s p] watt4 ,?is lamp gave an av]age ( #ege c&lep[] 7sph]ical7 9 all directions1 ?\gh x 0 call$ ! #bjjj cp 7c&lep[]7 arc z "u ! be/ possible conditions x c\ld give ?is c&lep[] 9 "o direction4 ,lat] a #f4f amp]e arc 0 develop$4 ,?is 0 call$ ! 8#abjj cp0 lamp & 0 n q z effici5t z ! #i4f amp]e lamp4 8,,sub-,,divid+ ,,! ,,electric ,,light0 ,:ile ! arc lamp 0 be+ comm]cially e/abli%$1 x 0 at once se5 t x 0 too l>ge a unit = h\sehold use4 ,_m inv5tors attack$ ! problem ( mak+ a small] unit1 or1 z x 0 call$1 8sub-divid+ ! electric light40 ,9 ! ,unit$ ,/ates !re 7 f\r m5 prom95t 9 ?is "w3 ,william ,e4 ,sawy]1 ,moses ,g4 ,f>m]1 ,hiram ,s4 ,maxim & ,?omas ,a4 ,edison4 ,^! m5 did n make small] arc lamps b all attempt$ to make an inc&esc5t lamp t w\ld op]ate on ! arc circuits4 ,illu/ration3 ,,sawy]',s ,,inc&esc5t ,,lamp1 #ahgh4 ,?is _h a graphite burn] op]at+ 9 nitrog5 gas4 ,illu/ration3 ,,f>m]',s ,,inc&esc5t ,,lamp1 #ahgh4 ,! graphite burn] op]at$ 9 nitrog5 gas4 ,?is lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,sawy] made sev]al lamps 9 ! ye>s #ahgh-gi along ! l9es ( ! ,russian sci5ti/s4 ,all 8 lamps _h a ?ick c>bon burn] op]at+ 9 nitrog5 gas4 ,!y _h a long glass tube clos$ at "o end & ! o!r cem5t$ to a brass base ?r\gh :i* ! gas 0 put 94 ,heavy flut$ wires connect$ ! burn] ) ! base to radiate ! heat1 9 ord] to keep ! jo9t 9 ! base cool4 ,! burn] 0 r5ewable by op5+ ! cem5t$ jo9t4 ,f>m]'s lamp consi/$ ( a pair ( heavy copp] rods m\nt$ on a rubb] cork1 betwe5 :i* a graphite rod 0 m\nt$4 ,?is 0 ins]t$ 9 a glass bulb & op]at$ 9 nitrog5 gas4 ,maxim made a lamp hav+ a c>bon burn] op]at+ 9 a r>efi$ hydroc>bon vapor4 ,he also made a lamp consi/+ ( a %eet ( plat9um op]at+ 9 air4 ,,edison',s ,,inv5tion ,,( ,a ,,practical ,,inc&esc5t ,,lamp ,edison began ! /udy ( ! problem 9 ! spr+ ( #ahgh4 ,he _h a well-equipp$ laboratory at ,m5lo ,p>k1 ,new ,j]sey1 ) sev]al able assi/ants & a numb] ( workm51 ab\t a hundr$ p all told4 ,he _h made a numb] ( well-kn[n inv5tions1 among :i* 7 ! quadruplex telegraph :]eby f\r messages c\ld be s5t simultane\sly ov] "o wire1 ! c>bon telephone transmitt] )\t :i* ,bell's telephone receiv] w\ld h be5 impracticable1 & ! phonograph4 ,all ( ^! are 9 use today1 s ,edison 0 em95tly fitt$ to attack ! problem4 ,illu/ration3 ,,maxim',s ,,inc&esc5t ,,lamp1 #ahgh4 ,! c>bon burn] op]at$ 9 a r>efi$ hydroc>bon vapor4 ,?is lamp is 9 ! collection ( ! ,smi?sonian ,in/itution4 ,edison's fir/ exp]im5ts 7 to confirm ! failures ( o!r exp]im5t]s4 ,conv9c$ ( ! seem+ impossibility ( c>bon1 he turn$ 8 att5tion to plat9um z a light giv+ elem5t4 ,realiz+ ! importance ( op]at+ plat9um close to its melt+ temp]ature1 he design$ a lamp :i* _h a !rmo/atic arrangem5t s t ! burn] w\ld be automatically %ort circuit$ ! mom5t its temp]ature became dang]\sly close to melt+4 ,! burn] consi/$ ( a d\ble helix ( plat9um wire )9 :i* 0 a rod4 ,:5 ! temp]ature ( ! plat9um became too high1 ! rod 9 exp&+ w\ld %ort circuit ! plat9um4 ,! plat9um cool$ at once1 ! rod contract$ op5+ ! %ort circuit & all[+ curr5t to fl[ ?r\gh ! burn] aga94 ,8 fir/ inc&esc5t lamp pat5t cov]$ ?is lamp4 ,8 next pat5t cov]$ a simil> lamp ) an improv$ !rmo/at consi/+ ( an exp&+ diaphragm4 ,bo? ( ^! lamps 7 design$ = use on s]ies circuits4 ,illu/ration3 ,,edison',s ,,fir/ ,,exp]im5tal ,,lamp1 #ahgh4 ,! burn] 0 a coil ( plat9um wire :i* 0 protect$ f op]at+ at too high a temp]ature by a !rmo/at4 ,! only sy/em ( di/ribut+ electricity1 kn[n at t "t1 0 ! s]ies sy/em4 ,9 ?is sy/em curr5t g5]at$ 9 ! dynamo armature fl[$ ?r\gh ! field coils1 out to "o lamp aft] ano!r ov] a wire1 & !n back to ! dynamo4 ,!re 7 no means by :i* "o lamp c\ld be turn$ on & (f )\t do+ ! same ) all ! o!rs on ! circuit4 ,edison realiz$ t :ile ?is 0 satisfactory = /reet light+ :]e arcs 7 g5]ally us$1 x nev] w\ld be comm]cial = h\sehold light+4 ,he !re=e decid$ t a practical inc&esc5t electric light+ sy/em mu/ be patt]n$ aft] gas light+ ) :i* x w\ld compete4 ,he !re=e made an int5sive /udy ( gas di/ribution & reason$ t a con/ant pressure electrical sy/em c\ld be made simil> to t ( gas4 ,! fir/ problem 0 !re=e to design a dynamo t w\ld give a con/ant pressure in/ead ( con/ant curr5t4 ,he !re=e reason$ t ! int]nal resi/ance ( ! armature mu/ be v l[ or ! voltage w\ld fall z curr5t 0 tak5 f ! dynamo4 ,sci5ti/s _h %[n t ! mo/ economical use ( electricity f a prim>y batt]y 0 :]e ! ext]nal resi/ance ( ! load 0 ! same z ! int]nal resi/ance ( ! batt]y1 or 9 o!r words1 #ej p] c5t 0 ! maximum possible effici5cy4 ,illu/ration3 ,,diagram ,,( ,,con/ant ,,curr5t ,,s]ies ,,sy/em4 ,?is1 9 #ahgh1 0 ! only me?od ( di/ribut+ electric curr5t4 ,illu/ration3 ,,diagram ,,( ,,edison',s ,,multiple ,,sy/em1 #ahgi4 ,edison inv5t$ ! multiple sy/em ( di/ribut+ electric curr5t1 n[ univ]sally us$4 ,:5 ,edison propos$ a v l[ resi/ance armature s t ! dynamo w\ld h an effici5cy ( #ij p] c5t at full load1 he 0 ridicul$4 ,nev]!less he w5t ahead & made "o :i* atta9$ ?is4 ,! armature consi/$ ( drum-w\nd insulat$ copp] rods1 ! armature core hav+ circul> %eets ( iron ) pap] betwe5 to r$uce ! eddy curr5ts4 ,!re 7 two v]tical fields above & connect$ 9 %unt ) ! armature4 ,x g5]at$ electricity at ab\t a hundr$ volts con/ant pressure & c\ld supply curr5t up to ab\t #fj amp]es at ?is pressure4 ,x !re=e _h a capacity1 9 ! pres5t t]m9ology1 ( ab\t #f kil[atts 7or #h horsep[]74 ,illu/ration3 ,,edison ,,dynamo1 #ahgi4 ,edison made a dynamo t 0 #ij p] c5t effici5t :i* sci5ti/s said 0 impossible4 ,?is dynamo is 9 ! collection ( ! ,smi?sonian ,in/itution & 0 "o ( ! ma*9es on ! /eam%ip ,columbia1 ! fir/ comm]cial in/allation ( ! ,edison lamp4 ,a multiple sy/em ( di/ribution w\ld make ea* lamp indep5d5t ( e o!r & ) a dynamo made = su* a sy/em1 ! next ?+ 0 to design a lamp = x4 ,hav+ a pressure ( ab\t a hundr$ volts to cont5d )1 ! lamp1 9 ord] to take a small am\nt ( curr5t1 mu/1 to comply ) ,ohm's law1 h a high resi/ance4 ,he !re=e w\nd _m feet ( f9e plat9um wire on a spool ( pipe clay & made 8 fir/ high resi/ance lamp4 ,he us$ 8 diaphragm !rmo/at to protect ! plat9um f melt+1 &1 z n[ seems obvi\s b 0 n to all s-call$ electricians at t "t1 ! !rmo/at 0 arrang$ to op5 circuit in/ead ( %ort circuit ! burn] :5 x became too hot4 ,?is lamp app>5tly solv$ ! problem1 &1 9 ord] to protect ! plat9um f ! oxyg5 ( ! air1 he coat$ x ) oxide ( zirconium4 ,un=tunately zirconia1 :ile an insulator at ord9>y temp]atures1 becomes1 z is n[ kn[n1 a conductor ( electricity :5 heat$1 s t ! lamp %ort circuit$ itself :5 x 0 light$4 ,illu/ration3 ,,edison',s ,,high ,,resi/ance ,,plat9um ,,lamp1 #ahgi4 ,?is lamp _h a high resi/ance burn]1 necess>y = ! multiple sy/em4 ,illu/ration3 ,,edison',s ,,high ,,resi/ance ,,plat9um ,,9 ,,vacuum ,,lamp1 #ahgi4 ,?is exp]im5tal lamp l$ to ! inv5tion ( ! successful c>bon filam5t lamp4 ,dur+ 8 exp]im5ts he _h f\nd t plat9um became exce$+ly h>d aft] x _h be5 heat$ sev]al times to inc&esc5ce by curr5t fl[+ ?r\gh x4 ,?is app>5tly rais$ its melt+ temp]ature s he 0 able to increase ! op]at+ temp]ature & !re=e greatly increase ! c&lep[] ( 8 lamps aft] !y _h be5 heat$ a few times4 ,exam9ation ( ! plat9um "u a microscope %[$ x to be mu* less por\s aft] heat+1 s he reason$ t gases 7 occlud$ ?r\gh\t ! plat9um & 7 driv5 out by ! heat4 ,?is l$ him to make a lamp ) a plat9um wire to op]ate 9 vacuum1 z he ?\ght t m ( ! occlud$ gases w\ld come out "u su* circum/ances4 ,illu/ration3 ,,edison',s ,,c>bon ,,lamp ,,( ,,octob] #ba1 #ahgi4 ,?is exp]im5tal lamp1 hav+ a high resi/ance c>bon filam5t op]at+ 9 a high vacuum ma9ta9$ by an all-glass globe1 0 ! key/one ( ,edison's successful inc&esc5t light+ sy/em4 ,all inc&esc5t lamps made today embody ! basic features ( ?is lamp4 ,?is replica is 9 ! ,smi?sonian ,in/itution exhibit ( ,edison lamps4 ,! orig9al 0 de/roy$4 ,^! lamps 7 exp5sive to make1 &1 kn[+ t he c\ld get ! requisite high resi/ance at mu* less co/ f a long & sl5d] piece ( c>bon1 he ?\ght he might be able to make ! c>bon la/ 9 ! high vacuum he _h be5 able to obta9 f ! newly inv5t$ ,geissl] & ,spr5gel m]cury air pumps4 ,aft] sev]al trials he f9ally 0 able to c>bonize a piece ( ord9>y sew+ ?read4 ,?is he m\nt$ 9 a "o-piece all glass globe1 all jo9ts fus$ by melt+ ! glass toge!r1 :i* he consid]$ 0 ess5tial 9 ord] to ma9ta9 ! high vacuum4 ,plat9um wires 7 fus$ 9 ! glass to connect ! c>boniz$ ?read inside ! bulb ) ! circuit outside z plat9um has ! same coeffici5t ( expansion z glass & h5ce ma9ta9s an airtight jo9t4 ,he reason$ t !re w\ld be occlud$ gases 9 ! c>boniz$ ?read :i* w\ld imm$iately burn up if ! slighte/ trace ( oxyg5 7 pres5t1 s he heat$ ! lamp :ile x 0 /ill on ! exhau/ pump aft] a high degree ( vacuum _h be5 obta9$4 ,?is 0 accompli%$ by pass+ a small am\nt ( curr5t ?r\gh ! 8filam5t10 z he call$ x1 g5tly heat+ x4 ,imm$iately ! gases />t$ com+ out1 & x took eight h\rs m on ! pump be=e !y /opp$4 ,! lamp 0 !n seal$ & ready = trial4 ,illu/ration3 ,,demon/ration ,,( ,,edison',s ,,inc&esc5t ,,light+ ,,sy/em4 ,%[+ view ( ,m5lo ,p>k ,laboratory ,build+s1 #ahhj4 ,on ,octob] #ba1 #ahgi1 curr5t 0 turn$ into ! lamp & x la/$ =ty-five h\rs be=e x fail$4 ,a pat5t 0 appli$ = on ,novemb] #d? ( t ye> & grant$ ,janu>y #bg1 #ahhj4 ,all inc&esc5t lamps made today embody ! basic features ( ?is lamp4 ,edison imm$iately began a se>*+ inve/igation ( ! be/ mat]ial = a filam5t & soon f\nd t c>boniz$ pap] gave sev]al hundr$ h\rs life4 ,?is made x comm]cially possible1 s 9 ,decemb]1 #ahgi1 x 0 decid$ t a public demon/ration ( 8 inc&esc5t light+ sy/em %\ld be made4 ,wires 7 run to sev]al h\ses 9 ,m5lo ,p>k1 ,n4 ,j41 & lamps 7 also m\nt$ on poles1 light+ ! c\ntry roads 9 ! neighborhood4 ,an article appe>$ 9 ! ,new ,york ,h]ald on ,sunday1 ,decemb] #ba1 #ahgi1 describ+ ,edison's inv5tion & tell+ ( ! public demon/ration to be giv5 dur+ ! ,*ri/mas holidays4 ,?is occupi$ ! entire fir/ page ( ! pap]1 & creat$ su* a furor t ! ,p5nsylvania ,railroad _h to run special tra9s to ,m5lo ,p>k to accommodate ! cr[ds4 ,! fir/ comm]cially successful in/allation ( ! ,edison inc&esc5t lamps & light+ sy/em 0 made on ! /eam%ip ,columbia1 :i* />t$ ,may #b1 #ahhj1 on a voyage ar\nd ,cape ,horn to ,san ,francisco1 ,calif4 ,! c>boniz$ pap] filam5t ( ! fir/ comm]cial inc&esc5t lamp 0 q fragile4 ,e>ly 9 #ahhj c>boniz$ bamboo 0 f\nd to be n only /urdy b made an ev5 bett] filam5t ?an pap]4 ,! %ape ( ! bulb 0 also *ang$ f r\nd to pe> %ape1 be+ bl[n f "o in* tub+4 ,lat] ! bulbs 7 bl[n directly f molt5 glass4 ,illu/ration3 ,,dynamo ,,room1 ,s4 ,s4 ,,columbia4 ,! fir/ comm]cial in/allation ( ! ,edison ,lamp1 />t$ ,may #b1 #ahhj4 ,"o ( ^! orig9al dynamos is on exhibit at ! ,smi?sonian ,in/itution4 ,z x 0 inconv5i5t to connect ! wires to ! b9d+ po/s ( a new lamp e "t a burn$ out lamp _h to be replac$1 a base & socket = x 7 develop$4 ,! e>lie/ =m ( base consi/$ simply ( b5d+ ! two wires ( ! lamp back on ! neck ( ! bulb & hold+ !m 9 place by wrapp+ /r+ ar\nd ! neck4 ,! socket consi/$ ( two pieces ( %eet copp] 9 a holl[ piece ( wood4 ,! lamp 0 ins]t$ 9 ?is1 ! two-wire t]m9als ( ! lamp mak+ contact ) ! two-%eet copp] t]m9als ( ! socket1 ! lamp be+ rigidly held 9 ! socket by a ?umb screw :i* =c$ ! socket t]m9als tight aga9/ ! neck ( ! bulb4 ,illu/ration3 ,,orig9al ,,socket ,,= ,,inc&esc5t ,,lamps1 #ahhj4 ,illu/ration3 ,,wire ,,t]m9al ,,base ,,lamp1 #ahhj4 ,?is crude =m ( lamp base fitt$ ! orig9al =m ( lamp socket pictur$ above4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,?is crude arrangem5t 0 *ang$ 9 ! latt] "p ( #ahhj to a screw %ell & a r+ = ! base t]m9als1 wood be+ us$ = insulation4 ,! socket 0 correspond+ly *ang$4 ,?is 0 a v bulky affair1 s ! base 0 *ang$ to a cone-%ap$ r+ & a screw %ell = t]m9als4 ,wood 0 us$ = insulation1 :i* a %ort "t aft] 0 *ang$ to pla/] ( ,p>is z ?is 0 also us$ to fa/5 ! base to ! bulb4 ,x 0 soon f\nd t ! t5sion creat$ betwe5 ! two t]m9als ( ! base :5 ! lamp 0 firmly screw$ 9 ! socket (t5 caus$ ! pla/] base to pull ap>t1 s ! %ape ( ! base 0 aga9 *ang$ e>ly 9 #ahha1 to ! =m 9 use today4 ,an improv$ me?od ( connect+ ! ends ( ! filam5t to ! lead+-9 wires 0 adopt$ e>ly 9 #ahha4 ,=m]ly ?is 0 accompli%$ by a delicate clamp hav+ a bolt & nut4 ,! improvem5t consi/$ ( copp] plat+ ! filam5t to ! lead+-9 wire4 ,illu/ration3 ,,orig9al ,,screw ,,base ,,lamp1 #ahhj4 ,?is fir/ screw base1 consi/+ ( a screw %ell & r+ = t]m9als ) wood = insulation1 0 a v bulky affair4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,illu/ration3 ,,improv$ ,,screw ,,base ,,lamp1 #ahha4 ,! t]m9als ( ?is base consi/$ ( a cone %ap$ r+ & a screw %ell4 ,at fir/ wood 0 us$ = insulation1 lat] pla/] ( p>is :i* 0 also us$ to fa/5 ! base to ! bulb4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,9 ! e>ly "p ( ! ye> #ahha ! lamps 7 made 8eight to ! horsep[]40 ,ea* lamp1 !re=e1 consum$ a little less ?an #ajj watts1 & 0 design$ to give #af c&lep[] 9 a horizontal direction4 ,! av]age c&lep[] 7sph]ical7 9 all directions 0 ab\t #gg p] c5t ( ?is1 h5ce z ! mod]n t]m 8lum50 is #ab4eg sph]ical c&lep[]1 ^! lamps _h an initial effici5cy ( ab\t #a4g lum5s p] watt4 ,! lamps black5$ consid]ably dur+ _! life s t j be=e !y burn$ out _! c&lep[] 0 less ?an half t :5 new4 ,?us _! mean effici5cy ?r\gh\t life 0 ab\t #a4a l-p-w 7lum5s p] watt74 ,^! figures are int]e/+ 9 comp>ison ) ! mod]n #ajj-watt gas-fill$ tung/5-filam5t lamp :i* has an initial effici5cy ( #ab4i1 & a mean effici5cy ( #aa4h1 l-p-w4 ,9 o!r words ! equival5t 7wattage7 size ( mod]n lamp gives ov] sev5 times :5 new1 & elev5 times on ! av]age1 z mu* light = ! same en]gy consumption z ,edison's fir/ comm]cial lamp4 ,9 ! latt] "p ( #ahha ! effici5cy 0 *ang$ to 8t5 lamps p] horsep[]10 equival5t to #b l-p-w initially4 ,two sizes ( lamps 7 made3 #af cp = use on #aaj-volt circuits & #h cp = use ei!r direct on #ee volts or two 9 s]ies on #aaj-volt circuits4 ,illu/ration3 ,,f9al ,,=m ,,( ,,screw ,,base1 #ahha4 ,) pla/] ( p>is1 ! previ\s =m ( base 0 apt to pull ap>t :5 ! lamp 0 firmly screw$ into ! socket4 ,! =m ( ! base 0 !re=e *ang$ to t %[n1 :i* ov]came ^! difficulties1 & :i* has be5 us$ ev] s9ce4 ,! lamp %[n 0 /&>d = ?ree ye>s & is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,,edison',s ,,?ree-,,wire ,,sy/em ,! di/ance at :i* curr5t c be economically deliv]$ at #aaj volts pressure is limit$1 z w be se5 f a /udy ( ,ohm's law4 ,! loss ( p[] 9 ! di/ribut+ wires is proportional to ! squ>e ( ! curr5t fl[+4 ,if ! voltage be d\bl$1 ! am\nt ( curr5t is halv$1 = a giv5 am\nt ( electric p[] deliv]$1 s t ! size ( ! di/ribut+ wires c !n be r$uc$ to "o-qu>t] = a giv5 loss 9 !m4 ,at t "t 7#ahha7 x 0 impossible to make #bbj-volt lamps1 & ?\gh !y are n[ available1 _! use is uneconomical1 z _! effici5cy is mu* poor] ?an t ( #aaj-volt inc&esc5t lamps4 ,edison inv5t$ a di/ribut+ sy/em t _h two #aaj-volt circuits1 ) "o wire call$ ! neutral1 common to bo? circuits s t ! pressure on ! two outside wires 0 #bbj volts4 ,! neutral wire _h only to be l>ge en\gh to c>ry ! diff]5ce betwe5 ! curr5ts fl[+ 9 ! two circuits4 ,z ! load c\ld be s arrang$ t x w\ld be approximately equal at all times on bo? circuits1 ! neutral wire c\ld be relatively small 9 size4 ,?us ! ?ree-wire sy/em result$ 9 a sav+ ( #fj p] c5t 9 copp] ov] ! two-wire sy/em or1 = ! same am\nt ( copp]1 ! di/ance t curr5t c\ld be deliv]$ 0 m ?an d\bl$4 ,illu/ration3 ,,diagram ,,( ,,edison',s ,,?ree-,,wire ,,sy/em1 #ahha4 ,?is sy/em r$uc$ ! co/ ( copp] 9 ! multiple di/ribut+ sy/em #fj p] c5t4 ,,developm5t ,,( ,,! ,,alt]nat+ ,,curr5t ,,con/ant ,,pot5tial ,,sy/em ,! di/ance t curr5t c be economically di/ribut$1 z has be5 %[n1 dep5ds ^u ! voltage us$4 ,if1 !re=e1 curr5t c\ld be s5t out at a high voltage & ! pressure br\ght d[n to t desir$ at ! v>i\s po9ts to :i* x is di/ribut$1 su* di/ribution c\ld cov] a mu* great] area4 ,luci5 ,gaul>d 0 a ,fr5* inv5tor & 0 back$ by an ,engli%man nam$ ,john ,d4 ,gibbs4 ,ab\t #ahhb !y pat5t$ a s]ies alt]nat+-curr5t sy/em ( di/ribution4 ,!y _h inv5t$ :at is n[ call$ a trans=m] :i* consi/$ ( two sep>ate coils ( wire m\nt$ on an iron core4 ,all ! prim>y coils 7 connect$ 9 s]ies1 :i*1 :5 curr5t w5t ?r\gh !m1 induc$ a curr5t 9 ! second>y coils4 ,lamps 7 connect$ 9 multiple on ea* ( ! second>y coils4 ,an ,am]ican pat5t 0 appli$ = on ! trans=m]1 b 0 refus$ on ! basis t 8m curr5t _c be tak5 f x ?an is put 940 ,:ile ?is is true if ! ^w en]gy 7 us$1 ! trans=m] c supply a great] curr5t at a l[] voltage 7or vice v]sa7 ?an is put 91 ! ratio be+ 9 proportion to ! relative numb] ( turns 9 ! prim>y & second>y coils4 ,! trans=m] 0 treat$ ) ridicule & ,gaul>d di$ "u di/ress+ circum/ances4 ,illu/ration3 ,,diagram ,,( ,,/anley',s ,,alt]nat+ ,,curr5t ,,multiple ,,sy/em1 #ahhe4 ,?is sy/em is n[ univ]sally us$ = di/ribut+ electric curr5t long di/ances4 ,in=mation reg>d+ ! trans=m] came to ! att5tion ( ,william ,/anley1 an ,am]ican1 9 ! latt] "p ( #ahhe4 ,he made an int5sive /udy ( ! s*eme1 & develop$ a trans=m] 9 :i* ! prim>y coil 0 connect$ 9 multiple on a con/ant pot5tial alt]nat+-curr5t high-voltage sy/em4 ,f ! second>y coil a l[] con/ant voltage 0 obta9$4 ,an exp]im5tal in/allation 0 made at ,great ,b>r+ton1 ,mass41 9 ! e>ly "p ( #ahhf1 ! fir/ comm]cial in/allation be+ made 9 ,buffalo1 ,new ,york1 9 ! latt] "p ( ! ye>4 ,?is s*eme enabl$ curr5t to be economically di/ribut$ to mu* great] di/ances4 ,! voltage ( ! high-t5sion circuit has be5 gradually increas$ z ! art has progress$ f ab\t a ?\s& volts to ov] two hundr$ ?\s& volts pressure 9 a rec5t in/allation 9 ,cali=nia1 :]e electric p[] is transmitt$ ov] two hundr$ miles4 ,,inc&esc5t ,,lamp ,,developm5ts1 #ahhd-ahid ,9 #ahhd ! r+ ( pla/] ar\nd ! top ( ! base 0 omitt$2 9 #ahhf an improvem5t 0 made by pa/+ ! filam5t to ! lead+-9 wires ) a c>bon pa/e in/ead ( ! electro-plat+ me?od2 & 9 #ahhh ! l5g? ( ! base 0 increas$ s t x _h m ?reads4 ,sev]al conc]ns />t$ mak+ inc&esc5t lamps1 ! filam5ts be+ made by c>boniz+ v>i\s sub/ances4 8,p>*m5tiz$0 ?read consi/$ ( ord9>y ?read pass$ ?r\gh sulphuric acid4 8,tamad9e0 0 cellulose 9 ! %eet =m1 pun*$ out 9 ! %ape ( ! filam5t4 ,squirt$ cellulose 9 ! =m ( a ?read 0 also us$4 ,?is 0 made by dissolv+ absorb5t cotton 9 z9c *loride1 ! result+ syrup be+ squirt$ ?r\gh a die into alcohol :i* h>d5$ ! ?read ?us =m$4 ,?is ?read 0 wa%$ 9 wat]1 dri$ 9 ! air & !n cut to prop] l5g? & c>boniz$4 ,illu/ration3 ,,/&>d ,,edison ,,lamp1 #ahhd4 ,! r+ ( pla/] ar\nd ! neck ( previ\s lamps 0 omitt$4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,illu/ration3 ,,/&>d ,,edison ,,lamp1 #ahhh4 ,! l5g? ( ! base 0 increas$ s x _h m ?reads4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,! filam5t 0 improv$ by coat+ x ) graphite4 ,"o me?od1 adopt$ ab\t #ahhh1 0 to dip x 9 a hydroc>bon liquid be=e c>boniz+4 ,ano!r1 m g5]ally adopt$ 9 #ahic 0 a process orig9ally inv5t$ by ,sawy]1 "o ( ! ,am]icans :o _h attempt$ to 8sub-divide ! electric light0 9 #ahgh-gi4 ,?is process consi/$ ( pass+ curr5t ?r\gh a c>boniz$ filam5t 9 an atmosph]e ( hydroc>bon vapor4 ,! hot filam5t decompos$ ! vapor1 deposit+ graphite on ! filam5t4 ,! graphite coat$ filam5t improv$ x s x c\ld op]ate at #c lum5s p] watt 7initial effici5cy74 ,lamps ( #bj1 #bd1 #cb & #ej c&lep[] 7 develop$ = #aaj-volt circuits4 ,lamps 9 v>i\s sizes f #ab to #cf cp 7 made = use on /orage batt]ies hav+ v>i\s numb]s ( cells & giv+ a voltage ( f #bj to #dj volts4 ,m9iature lamps ( f to #b cp = use on dry batt]ies ( f #b to #e volts1 & #c to #f cp on #e to #ab volts1 7 also made4 ,^! c\ld also be connect$ 9 s]ies on #aaj volts = fe/oons4 ,v small lamps ( cp ( #b to #d volts = use 9 d5ti/ry & surg]y 7 made available4 ,^! m9iature lamps _h no bases1 wires be+ us$ to connect !m to ! circuit4 ,illu/ration3 ,,/&>d ,,edison ,,lamp1 #ahid4 ,?is lamp _h a 8treat$0 cellulose filam5t1 p]mitt+ an effici5cy ( #c lum5s p] watt :i* has nev] be5 exce$$ 9 a c>bon lamp4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,lamps = #bbj-volt circuits 7 develop$ z ?is voltage 0 desirable = p[] purposes1 electric motors be+ us$1 & a few lamps 7 ne$$ on su* circuits4 ,!y are less effici5t & m exp5sive ?an #aaj-volt lamps1 _! use be+ ju/ifi$ h[ev] only :5 x is uneconomical to h a sep>ate #aaj-volt circuit = light+4 ,! lamps 7 made 9 sizes f #af to #ej c&lep[]4 ,illu/ration3 ,edison4 ,?omson-,h\/on4 ,we/+h\se4 ,bru%-,swan4 ,edi-,swan ,edi-,swan ,unit$ ,/ates4 ,hawkeye4 7s+le contact74 7d\ble contact74 ,ft4 ,wayne ,j5ny4 ,ma!r or ,p]k9s4 ,loomis4 ,s*aeff] or ,national4 ,indianapolis ,j5ny4 ,siem5s ,halske4 ,,v>i\s ,,/&>d ,,bases ,,9 ,,use1 #ahib4 ,illu/ration3 ,,?omson-,,h\/on ,,socket4 ,illu/ration3 ,,we/+h\se ,,socket4 ,electric /reet railway sy/ems us$ a voltage 9 ! neighborhood ( #eej1 & lamps 7 design$ to burn five 9 s]ies on ?is voltage4 ,^! lamps 7 diff]5t f ! /&>d #aaj-volt lamps al?\gh !y 7 made = ab\t ?is voltage4 ,z !y 7 burn$ 9 s]ies1 ! lamps 7 select$ to op]ate at a def9ite curr5t in/ead ( at a def9ite voltage1 s t ! lamps :5 burn$ 9 s]ies w\ld op]ate at ! prop] temp]ature to give prop] life results4 ,su* lamps w\ld !re=e v>y consid]ably 9 individual volts1 & h5ce w\ld n give good s]vice if burn$ on #aaj-volt circuits4 ,! c&elabra screw base & socket & ! m9iature screw base & socket 7 lat] develop$4 ,ornam5tal c&elabra base lamps 7 made = use direct on #aaj volts1 small] sizes be+ op]at$ 9 s]ies on ?is voltage4 ,! =m] gave ab\t #aj cp1 ! latt] 9 v>i\s sizes f #d to #h cp4 ,! m9iature screw base lamps 7 = l[ volt light+4 ,illu/ration3 ,?omson-,h\/on4 ,we/+h\se4 ,,adapt]s ,,= ,,edison ,,screw ,,sockets1 #ahib4 ,next to ! ,edison base1 ! ,?omson-,h\/on & ,we/+h\se bases 7 ! mo/ popul>4 ,by use ( ^! adapt]s1 ,edison base lamps c\ld be us$ 9 ,t-,h & ,we/+h\se sockets4 ,! v>i\s manufactur]s ( lamps 9 ne>ly e in/ance made bases t 7 v diff]5t f "o ano!r4 ,no less ?an f\rte5 diff]5t /&>d bases & sockets came into comm]cial use4 ,^! 7 kn[n z1 ,bru%-,swan1 ,edison1 ,edi-,swan 7d\ble contact71 ,edi-,swan 7s+le contact71 ,=t ,wayne ,j5ny1 ,hawkeye1 ,indianapolis ,j5ny1 ,loomis1 ,ma!r or ,p]k9s1 ,s*aeff] or ,national1 ,siem5s ,halske1 ,?omson-,h\/on1 ,unit$ ,/ates & ,we/+h\se4 ,9 addition !re 7 lat] l>g] siz$ bases made = use on s]ies circuits4 ,^! 7 call$ ! ,b]n/e91 ,heisl]1 ,l>ge ,edison1 ,municipal ,b]n/e91 ,municipal ,edison1 ,?omson-,h\/on 7alt]nat+ circuit7 & ,?omson-,h\/on 7arc circuit74 ,"s ( ^! bases disappe>$ f use & 9 #aijj ! proportion 9 ! ,unit$ ,/ates 0 ab\t #gj p] c5t ,edison1 #ae p] c5t ,we/+h\se1 #aj p] c5t ,?omson-,h\/on & #e p] c5t = all ! o!rs rema9+4 ,a campaign 0 />t$ to /&>dize ! ,edison base1 adapt]s be+ sold at co/ = ! ,we/+h\se & ,?omson-,h\/on sockets s t ,edison base lamps c\ld be us$4 ,9 a few ye>s ! desir$ results 7 obta9$ s t n[ !re are no o!r sockets 9 ! ,unit$ ,/ates b ! ,edison screw type = /&>d light+ s]vice4 ,?is applies also to all o!r c\ntries 9 ! _w except ,engl& :]e ! bayonet =m ( base & socket is /ill popul>4 ,illu/ration3 ,b]n/e94 ,heisl]4 ,?omson-,h\/on 7alt]nat+ curr5t74 ,?omson-,h\/on ,municipal ,edison4 ,municipal ,b]n/e94 7arc circuit74 ,,v>i\s ,,s]ies ,,bases ,,9 ,,use1 #ahib4 ,! above six bases h be5 sup]s$$ by ! 8,l>ge ,edison10 n[ call$ ! ,mogul ,screw base4 ,,! ,,edison 8,,municipal0 ,,/reet ,,light+ ,,sy/em ,illu/ration3 ,,edison 8,,municipal0 ,,sy/em1 #ahhe4 ,high voltage direct curr5t 0 g5]at$1 sev]al circuits op]at+ 9 multiple1 ?ree amp]e lamps burn+ 9 s]ies on ea* circuit4 ,photograph c\rtesy ( ,association ( ,edison ,illum9at+ ,companies4 ,! arc lamp c\ld n practically be made 9 a unit small] ?an ! s-call$ 8#abjj c&lep[]0 7#f4f amp]e7 or 8half0 size1 :i* really gave ab\t #cej sph]ical c&lep[]4 ,a dem& !re=e arose = a small /reet light+ unit1 & ,edison design$ 8 8,municipal0 /reet light+ sy/em to fill ?is requirem5t4 ,8 exp]i5ce 9 ! mak+ ( dynamos enabl$ him to make a direct curr5t bipol> con/ant pot5tial ma*9e t w\ld deliv] #ajjj volts :i* lat] 0 increas$ to #abjj volts4 ,!y 7 fir/ made 9 two sizes hav+ an output ( #ab & #cj amp]es respectively4 ,inc&esc5t lamps 7 made = #c amp]es 9 sev]al sizes f #af to #ej c&lep[]4 ,^! lamps 7 burn$ 9 s]ies on ! #abjj-volt direct curr5t sy/em4 ,?us ! #ab-;amp]e ma*9e _h a capacity = f\r s]ies circuits1 ea* tak+ #c amp]es1 ! s]ies circuits be+ connect$ 9 multiple across ! #abjj volts4 ,! numb] ( lamps on ea* s]ies circuit dep5d$ ^u _! size1 z ! voltage ( ea* lamp 0 diff]5t = ea* size1 be+ ab\t #a volts p] cp4 ,a popul> size 0 ! #cb-;c&lep[] unit1 :i* !re=e requir$ ab\t #de volts & h5ce at #c amp]es consum$ ab\t #ace watts4 ,all[+ #e p] c5t loss 9 ! wires ( ea* circuit1 !re 0 !re=e #aadj ( ! #abjj volts left = ! lamps4 ,h5ce ab\t #be #cb-;c&lep[] or #ej #af-;c&lep[] lamps c\ld be put on ea* s]ies circuit4 ,diff]5t sizes ( lamps c\ld also be put on ! same circuit1 ! numb] dep5d+ ^u ! aggregate voltage ( ! lamps4 ,illu/ration3 ,,edison ,,municipal ,,lamp1 #ahhe4 ,inside ! base 0 an arrangem5t by :i* ! lamp 0 automatically %ort circuit$ :5 x burn$ out4 ,a device 0 put 9 ! base ( ea* lamp to %ort circuit ! lamp :5 x burn$ out s z to prev5t all ! o!r lamps on t circuit f go+ out4 ,?is device consi/$ ( a piece ( wire put inside ! lamp bulb betwe5 ! two ends ( ! filam5t4 ,connect$ to ?is wire 0 a v ?9 wire inside ! base :i* held a piece ( metal compress$ aga9/ a spr+4 ,! spr+ 0 connect$ to "o t]m9al ( ! base4 ,%\ld ! lamp burn out1 curr5t w\ld jump f ! filam5t to ! wire 9 ! bulb1 & ! curr5t !n fl[$ ?r\gh ! ?9 wire to ! o!r t]m9al ( ! base4 ,! ?9 wire 0 melt$ by ! curr5t1 & ! spr+ pu%$ ! piece ( metal up %ort circuit+ ! t]m9als ( ! base4 ,?is s*eme 0 lat] simplifi$ by omitt+ ! wire1 spr+1 etc41 & sub/itut+ a piece ( metal :i* 0 prev5t$ f %ort circuit+ ! t]m9als ( ! base by a ?9 piece ( pap]4 ,:5 ! lamp burn$ out ! entire #abjj volts 0 impress$ across ?is piece ( pap]1 punctur+ x & s %ort circuit+ ! base t]m9als4 ,%\ld "o or m lamps g out on a circuit1 ! increase 9 curr5t above ! normal #c amp]es 0 prev5t$ by an adju/able resi/ance1 or an extra lot ( lamps :i* c\ld be turn$ on "o at a "t1 connect$ to ea* circuit & locat$ 9 ! p[] /ation "u ! control ( ! op]ator4 ,?is sy/em disappe>$ f use ) ! adv5t ( ! con/ant curr5t trans=m]4 ,,! ,,%unt ,,box ,,sy/em ,,= ,,s]ies ,,inc&esc5t ,,lamps ,illu/ration3 ,,%unt ,,box ,,sy/em1 #ahhg4 ,lamps 7 burn$ 9 s]ies on a high voltage alt]nat+ curr5t1 & :5 a lamp burn$ out all ! curr5t !n w5t ?r\gh its 8%unt box10 a reactance coil 9 multiple ) ea* lamp4 ,soon aft] ! comm]cial developm5t ( ! alt]nat+ curr5t con/ant pot5tial sy/em1 a s*eme 0 develop$ to p]mit ! use ( lamps 9 s]ies on su* circuits )\t ! necessity = %ort circuit+ a lamp %\ld x burn out4 ,a reactance1 call$ a 8%unt box0 & consi/+ ( a coil ( wire w\nd on an iron core1 0 connect$ across ea* lamp4 ,! %unt box consum$ b little curr5t :ile ! lamp 0 burn+4 ,%\ld "o lamp g out1 ! entire curr5t w\ld fl[ ?r\gh its %unt box & s ma9ta9 ! curr5t approximately con/ant4 ,x _h ! difficulty1 h[ev]1 t if sev]al lamps w5t out1 ! curr5t w\ld be mat]ially increas$ t5d+ to burn out ! rema9+ lamps on ! circuit4 ,?is sy/em also disappe>$ f use ) ! developm5t ( ! con/ant curr5t trans=m]4 ,,! ,,enclos$ ,,arc ,,lamp ,up to #ahic ! c>bons ( an arc lamp op]at$ 9 ! op5 air1 s t !y 7 rapidly consum$1 la/+ f eight to sixte5 h\rs dep5d+ on _! l5g? & ?ickness4 ,l\is ,b4 ,m>ks1 an ,am]ican1 f\nd t by plac+ a tight fitt+ globe ab\t ! arc1 ! life ( ! c>bons 0 increas$ t5 to twelve times4 ,?is 0 due to ! re/rict$ am\nt ( oxyg5 ( ! air 9 ! pres5ce ( ! hot c>bon tips & ?us ret>d$ _! consumption4 ,! am\nt ( light 0 some:at decreas$1 b ?is 0 m ?an (fset by ! less] exp5se ( trimm+ :i* also ju/ifi$ ! use ( m exp5sive bett] quality c>bons4 ,satisfactory op]ation requir$ t ! arc voltage be increas$ to ab\t #hj volts4 ,illu/ration3 ,,enclos$ ,,arc ,,lamp1 #ahic4 ,enclos+ ! arc l5g!n$ ! life ( ! c>bons1 !reby greatly r$uc+ ! co/ ( ma9t5ance4 ,?is lamp rapidly displac$ ! s]ies op5 arc4 ,an enclos$ arc lamp = use on #aaj-volt con/ant pot5tial circuits 0 also develop$4 ,a resi/ance 0 put 9 s]ies ) ! arc = use on #aaj-volt direct curr5t circuits1 to act z a balla/ 9 ord] to prev5t ! arc f tak+ too mu* curr5t & also to use up ! diff]5ce betwe5 ! arc voltage 7#hj7 & ! l9e voltage 7#aaj74 ,on alt]nat+ curr5t1 a reactance 0 us$ 9 place ( ! resi/ance4 ,! effici5cies 9 lum5s p] watt ( ^! arcs 7) cle> glassw>e71 all ( :i* h n[ disappe>$ f ! m>ket1 7 ab\t z foll[s3 #f4f amp]e #eaj watt direct curr5t 7,d4,c47 s]ies arc1 #h l-p-w4 #e4j amp]e #eej watt direct curr5t multiple 7#aaj-volt7 arc1 #d l-p-w4 #g4e amp]e #edj watt alt]nat+ curr5t 7,a4,c47 multiple 7#aaj-volt7 arc1 #d l-p-w4 ,illu/ration3 ,,op5 ,,flame ,,arc ,,lamp1 #ahih4 ,c]ta9 salts impregnat$ 9 ! c>bons produc$ a brilliantly lum9\s flame 9 ! arc /ream :i* enorm\sly increas$ ! effici5cy ( ! lamp4 ,illu/ration3 ,,enclos$ ,,flame ,,arc ,,lamp1 #aijh4 ,by cond5s+ ! smoke f ! arc 9 a cool+ *amb] x 0 practical to enclose ! flame arc1 !reby increas+ ! life ( ! c>bons4 ,! reason = ! big diff]5ce 9 effici5cy betwe5 ! s]ies & multiple direct-curr5t arc is t 9 ! latt] a l>ge am\nt ( electrical en]gy 7watts7 is lo/ 9 ! balla/ resi/ance4 ,:ile !re is a consid]able diff]5ce betwe5 ! inh]5t effici5cies ( ! ,d4 ,c4 & ,a4 ,c4 arcs !mselves1 ?is diff]5ce is r$uc$ 9 ! multiple ,d4 ,c4 & ,a4 ,c4 arc lamps z m watts are lo/ 9 ! resi/ance balla/ ( ! multiple ,d4 ,c4 lamp ?an are lo/ 9 ! reactance balla/ ( ! multiple ,a4 ,c4 lamp4 ,?is reactance gives ! ,a4 ,c4 lamp :at is call$ a 8p[]-factor40 ,! product ( ! amp]es 7#g4e7 times ! volts 7#aaj7 does n give ! true wattage 7#edj7 ( ! lamp1 s t ! actual volt-amp]es 7#hbe7 has to be multipli$ by a p[] factor1 9 ?is case ab\t #fe p] c5t1 to obta9 ! actual p[] 7watts7 consum$4 ,! reason is t ! in/antane\s v>y+ values ( ! alt]nat+ curr5t & pressure1 if multipli$ & av]ag$ ?r\gh\t ! complete alt]nat+ cycle1 d n equal ! av]age amp]es 7measur$ by an ammet]7 multipli$ by ! av]age voltage 7measur$ by a volt-met]74 ,t is1 ! maximum value ( ! curr5t fl[+ 7amp]es7 does n occur at ! same in/ant t ! maximum pressure 7voltage7 is on ! circuit4 ,,! ,,flame ,,arc ,,lamp ,ab\t #ahdd ,buns5 inve/igat$ ! effect ( introduc+ v>i\s *emicals 9 ! c>bon arc4 ,no?+ 0 done1 h[ev]1 until ,brem]1 a ,g]man1 exp]im5t$ ) v>i\s salts impregnat$ 9 ! c>bon electrodes4 ,9 #ahih he produc$ ! s-call$ flame arc1 :i* consi/$ ( c>bons impregnat$ ) calcium fluoride4 ,?is gave a brilliant yell[ light mo/ ( :i* came f ! arc flame1 & practically none f ! c>bon tips4 ,! arc op]at$ 9 ! op5 air & produc$ smoke :i* cond5s$ into a :ite p[d]4 ,! two c>bons 7 incl9$ d[nw>d at ab\t a #cj-;degree angle ) ea* o!r1 & 7 ( small diamet] b long1 #ah to #cj in*es1 hav+ a life ( ab\t #ab to #ae h\rs4 ,! tips ( ! c>bons project$ ?r\gh an inv]t$ e>!nw>e cup1 call$ ! 8economiz]10 ! :ite p[d] cond5s+ on ?is & act+ n only z an excell5t reflector b mak+ a dead air space above ! arc4 ,! arc 0 ma9ta9$ at ! tips ( ! c>bons by an electro-magnet ^: magnetic field 8blew0 ! arc d[n4 ,two flame arc lamps 7 burn$ 9 s]ies on #aaj-volt circuits4 ,!y consum$ #eej watts ea*1 giv+ an effici5cy ( ab\t #ce lum5s p] watt on direct curr5t4 ,on alt]nat+ curr5t ! effici5cy 0 ab\t #cj l-p-w4 ,by use ( b>ium salts impregnat$ 9 ! c>bons1 a :ite light 0 obta9$1 giv+ an effici5cy ( ab\t #ah l-p-w on direct curr5t & ab\t #ae on alt]nat+ curr5t4 ,^! figures cov] lamps equipp$ ) cle> glassw>e4 ,us+ /rontium salts 9 ! c>bons1 a r$ light 0 obta9$ at a consid]ably l[] effici5cy1 su* arcs on acc\nt ( _! color be+ us$ only to a limit$ ext5t = adv]tis+ purposes4 ,illu/ration3 ,,con/ant ,,curr5t ,,trans=m]1 #aijj4 ,?is conv]t$ alt]nat+ curr5t ( con/ant voltage into con/ant curr5t1 = use on s]ies circuits4 ,^! arcs 7 rem>kably effici5t b _! ma9t5ance exp5se 0 high4 ,lat]1 ab\t #aijh1 enclos$ flame arcs ) v]tical c>bons 7 made :i* increas$ ! life ( ! c>bons1 ! smoke be+ cond5s$ 9 cool+ *amb]s4 ,h[ev]1 _! ma9t5ance exp5se 0 /ill high4 ,!y h n[ disappe>$ f ! m>ket1 hav+ be5 displac$ by ! v effici5t gas-fill$ tung/5 filam5t inc&esc5t lamp :i* appe>$ 9 #aiac4 ,,! ,,con/ant ,,curr5t ,,trans=m] ,,= ,,s]ies ,,circuits ,ab\t #aijj ! con/ant curr5t trans=m] 0 develop$ by ,elihu ,?omson4 ,?is trans=ms curr5t tak5 f a con/ant pot5tial alt]nat+ curr5t circuit into a con/ant alt]nat+ curr5t = s]ies circuits1 ^: voltage v>ies ) ! load on ! circuit4 ,! trans=m] has two sep>ate coils2 ! prim>y be+ /ation>y & connect$ to ! con/ant pot5tial circuit & ! second>y be+ movable & connect$ to ! s]ies circuit4 ,! weight ( ! second>y coil is slightly und]balanc$ by a c\nt] weight4 ,curr5t fl[+ 9 ! prim>y induces curr5t 9 ! second>y1 ! two coils repell+ ea* o!r4 ,! /r5g? ( ! repell+ =ce dep5ds ^u ! am\nt ( curr5t fl[+ 9 ! two coils4 ,! core ( ! trans=m] is s design$ t ! c5tral "p1 :i* ! two coils surr\nd1 is magnetically m p[]ful close to ! prim>y coil ?an x is fur!r away4 ,:5 ! two coils are close toge!r a high] voltage is induc$ 9 ! second>y ?an if ! lat] 7 fur!r away f ! prim>y coil4 ,9 />t+1 ! two coils are pull$ ap>t by h& to prev5t too l>ge a curr5t fl[+ 9 ! s]ies circuit4 ,! second>y coil is all[$ to gradually fall & w come to re/ at a po9t :]e ! voltage induc$ 9 x produces ! normal curr5t 9 ! s]ies circuit1 ! repell+ =ce betwe5 ! two coils hold+ ! second>y at ?is po9t4 ,%\ld ! load 9 ! s]ies circuit *ange = any reason1 ! curr5t 9 ! s]ies circuit w\ld also *ange1 ?us *ang+ ! =ce repell+ ! two coils4 ,! second>y w\ld !re=e move until ! curr5t 9 ! s]ies circuit aga9 becomes normal4 ,! action is !re=e automatic1 & ! actual curr5t 9 ! s]ies circuit c be adju/$ )9 limits to ! desir$ am\nt1 by v>y+ ! c\nt]weight4 ,a da% pot is us$ to prev5t ! second>y coil f oscillat+ 7pump+7 too mu*4 ,9 ! con/ant curr5t trans=m]1 ! s]ies circuit is insulat$ f ! con/ant pot5tial circuit4 ,?is has _m advantages4 ,a simil> device1 call$ an automatic regulat+ reactance 0 develop$ :i* is slightly less exp5sive1 b x does n h ! advantage ( insulat+ ! two circuits f ea* o!r4 ,,enclos$ ,,s]ies ,,alt]nat+ ,,curr5t ,,arc ,,lamps ,! simplicity ( ! con/ant curr5t trans=m] soon drove ! con/ant direct-curr5t dynamo f ! m>ket4 ,an enclos$ arc lamp 0 !re=e develop$ = use on alt]nat+ con/ant curr5t4 ,two sizes ( lamps 7 made2 "o = #f4f amp]es consum+ #dej watts & hav+ an effici5cy ( ab\t #d lum5s p] watt1 & ! o!r #g4e amp]es1 #dhj watts & #e l-p-w 7cle> glassw>e74 ,^! lamps soon sup]s$$ ! direct curr5t s]ies arcs4 ,!y h n[ be5 sup]s$$ by ! m effici5t magnetite arc & tung/5 filam5t inc&esc5t lamps4 ,,s]ies ,,inc&esc5t ,,lamps ,,on ,,con/ant ,,curr5t ,,trans=m]s ,s]ies inc&esc5t lamps 7 made = use on con/ant curr5t trans=m]s sup]s$+ ! 8,municipal0 & 8,%unt ,box0 sy/ems4 ,! l>ge ,edison1 n[ call$ ! ,mogul ,screw base1 0 adopt$ & ! %ort circuit+ film cut-out 0 remov$ f ! base & plac$ betwe5 prongs atta*$ to ! socket4 ,illu/ration3 ,hold]4 ,socket4 ,hold] & socket4 ,,s]ies ,,inc&esc5t ,,lamp ,,socket ,,) ,,film ,,cut\t1 #aijj4 ,! 8,l>ge ,edison10 n[ call$ ,mogul ,screw1 base 0 /&>diz$ & ! %ort circuit+ device put on ! socket t]m9als4 ,! trans=m]s made = ! two sizes ( arc lamps1 produc$ #f4f & #g4e amp]es & inc&esc5t lamps1 9 v>i\s sizes f #af to #ej cp1 7 made = ^! curr5ts s t ! inc&esc5t lamps c\ld be op]at$ on ! same circuit ) ! arc lamps4 ,! c>bon s]ies inc&esc5t lamp1 h[ev]1 0 m effici5t if made = l[] curr5ts1 s #c-1 #d- & #e-;amp]e con/ant curr5t trans=m]s 7 made = inc&esc5t lamps design$ = ^! amp]es4 ,lat]1 h[ev]1 ) ! adv5t ( ! tung/5 filam5t1 ! #f4f-;amp]e s]ies tung/5 lamp 0 made ! /&>d1 z x 0 slightly m effici5t ?an ! l[] curr5t lamps1 & 0 made 9 sizes f #cb to #djj cp4 ,:5 ! m effici5t gas-fill$ tung/5 lamps 7 develop$1 ! sizes 7 fur!r increas$2 ! /&>d #f4f-;amp]e lamps n[ made are f #fj to #bejj cp4 ,,! ,,n]n/ ,,lamp ,dr4 ,wal!r ,n]n/1 ( ,g]many1 inve/igat+ ! r>e e>?s us$ 9 ! ,welsba* mantle1 develop$ an electric lamp hav+ a burn]1 or 8gl[]0 z x 0 call$1 consi/+ ( a mixture ( ^! oxides4 ,! ma9 +r$i5t 0 zirconia1 & ! gl[] op]at$ 9 ! op5 air4 ,x is a non-conductor :5 cold1 s _h to be heat$ be=e curr5t w\ld fl[ ?r\gh x4 ,?is 0 accompli%$ by an electric heat+ coil1 made ( plat9um wire1 locat$ j above ! gl[]4 ,z ! gl[] became heat$ & curr5t fl[$ ?r\gh x1 ! heat] 0 automatically disconnect$ by an electro-magnet cut-out4 ,illu/ration3 ,,n]n/ ,,lamp1 #aijj4 ,! burn]s consi/$ ma9ly ( zirconium oxide :i* _h to be heat$ be=e curr5t c\ld g ?r\gh !m4 ,! resi/ance ( ! gl[] decreases ) increase 9 curr5t1 s a /eady+ resi/ance 0 put 9 s]ies ) x4 ,?is consi/$ ( an iron wire m\nt$ 9 a bulb fill$ ) hydrog5 gas & 0 call$ a 8balla/40 ,iron has ! prop]ty ( increas+ 9 resi/ance ) increase 9 curr5t fl[+ ?r\gh x1 ?is increase be+ v m>k$ betwe5 c]ta9 temp]atures at :i* ! balla/ 0 op]at$4 ,! lamp 0 put on ! ,am]ican m>ket 9 #aijj = use on #bbj-volt alt]nat+ curr5t circuits4 ,! gl[] consum$ #j4d amp]e4 ,"o1 two1 ?ree1 f\r & six gl[] lamps 7 made1 consum+ #hh1 #aif1 #bgd1 #cib & #ebh watts respectively4 ,z mo/ ( ! light is ?r[n d[nw>d1 _! light output 0 g5]ally giv5 9 mean l[] hemisph]ical c&lep[]4 ,! multiple gl[] lamps 7 m effici5t ?an ! s+le gl[]1 ow+ to ! heat radiat$ f "o gl[] to ano!r4 ,_! effici5cies1 dep5d+ on ! size1 7 f ab\t #c to #e lum5s p] watt1 & _! av]age c&lep[] ?r\gh\t life 0 ab\t #hj p] c5t ( initial4 ,! lamp disappe>$ f ! m>ket ab\t #aiab4 ,illu/ration3 ,,diagram ,,( ,,n]n/ ,,lamp4 ,,! ,,coop]-,,hewitt ,,lamp ,9 #ahfj ,way discov]$ t if an electric circuit 0 op5$ betwe5 m]cury contacts a brilliant gre5i% color$ arc 0 produc$4 ,m]cury 0 an exp5sive metal & z ! c>bon arc seem$ to give ! mo/ desirable results1 no?+ fur!r 0 done = _m ye>s until ,dr4 ,pet] ,coop] ,hewitt1 an ,am]ican1 began exp]im5t+ ) x4 ,he f9ally produc$ an arc 9 vacuum 9 a "o-in* glass tube ab\t #ej in*es long = #aaj volts direct curr5t circuits1 :i* 0 comm]cializ$ 9 #aija4 ,! tube hangs at ab\t #ae degrees f ! horizontal4 ,! l[] end conta9s a small quantity ( m]cury4 ,! t]m9als are at ea* end ( ! tube1 & ! arc 0 fir/ />t$ by tilt+ ! tube by h& s t a ?9 /ream ( m]cury bridg$ ! two t]m9als4 ,curr5t imm$iately vaporiz$ ! m]cury1 />t+ ! arc4 ,a resi/ance is put 9 s]ies ) ! arc to ma9ta9 ! curr5t con/ant on direct curr5t con/ant voltage circuits4 ,automatic />t+ devices 7 lat] develop$1 "o ( :i* consi/$ ( an electro-magnet t tilt$ ! lamp1 & ! o!r ( an induction coil giv+ a high voltage :i*1 9 dis*>g+1 />t$ ! arc4 ,illu/ration3 ,,coop]-,,hewitt ,,m]cury ,,vapor ,,arc ,,lamp1 #aija4 ,?is gives a v effici5t light1 practically devoid ( r$ b ( high act9ic value1 s useful 9 photography4 ,?is lamp is p>ticul>ly useful 9 photography on acc\nt ( ! high act9ic value ( its light4 ,its light is v diffus$ & is practically devoid ( r$ rays1 s t r$ objects appe> black 9 its light4 ,! lamp consumes #c amp]es at #aaj volts direct curr5t 7#che watts7 hav+ an effici5cy ( ab\t #ab lum5s p] watt4 ,! m]cury arc is peculi> 9 t x acts z an electric valve t5d+ to let curr5t fl[ ?r\gh x only 9 "o direction4 ,?us on alt]nat+ curr5t1 ! curr5t impulses w readily g ?r\gh x 9 "o direction1 b ! arc w g out 9 ! o!r half cycle unless means are tak5 to prev5t ?is4 ,?is is accompli%$ by hav+ two t]m9als at "o end ( ! tube1 :i* are connect$ to *oke coils1 :i* 9 turn are connect$ to a s+le coil 7auto7 trans=m]4 ,! alt]nat+ curr5t supply ma9s are connect$ to wires tapp+ diff]5t p>ts ( ! coil ( ! auto trans=m]4 ,! c5t] ( ! coil ( ! auto trans=m] is connect$ ?r\gh an induction coil to ! o!r end ( ! tube4 ,by ?is means ! alt]nat+ curr5t impulses are s5t ?r\gh ! tube 9 "o direction1 "o half cycle f "o ( ! pairs ( t]m9als ( ! tube1 ! o!r half cycle f ! o!r t]m9al4 ,?us pulsat+ direct curr5t1 kept con/ant by ! induction coil1 fl[s ?r\gh ! tube1 ! pulsations ov]lapp+ ea* o!r by ! magnetic action ( ! *oke coils4 ,?is alt]nat+ curr5t lamp is />t$ by ! high voltage dis*>ge me?od4 ,x has a #ej-;in* l5g? ( tube1 consum+ ab\t #djj watts on #aaj volts4 ,its effici5cy is a little less ?an t ( ! direct curr5t lamp4 ,illu/ration3 ,,diagram ,,( ,,coop]-,,hewitt ,,lamp ,,= ,,use ,,on ,,alt]nat+ ,,curr5t4 ,! m]cury arc is inh]5tly = use on direct curr5t1 b by means ( reactance coils1 x c be op]at$ on alt]nat+ curr5t4 ,,! ,,lum9\s ,,or ,,magnetite ,,arc ,,lamp ,ab\t #aija ,dr4 ,*>les ,p4 ,/e9metz1 ,s*5ectady1 ,n4 ,y41 /udi$ ! effect ( metallic salts 9 ! arc flame4 ,dr4 ,willis ,r4 ,:itney1 also ( ,s*5ectady1 & director ( ! rese>* laboratory ( ! organization ( :i* ,dr4 ,/e9metz is ! consult+ eng9e]1 foll[$ ) "s fur!r "w along ?is l9e4 ,! results ( ?is "w 7 incorporat$ 9 a comm]cial lamp call$ ! magnetite arc lamp1 ?r\gh ! ef=ts ( ,c4 ,a4 ,b4 ,halvorson1 ,jr41 at ,lynn1 ,mass4 ,! negative electrode consi/s ( a pulv]iz$ mixture ( magnetite 7a v>iety ( iron ore7 & o!r sub/ances pack$ tightly 9 an iron tube4 ,! positive electrode is a piece ( copp] %ea!d 9 iron to prev5t oxidization ( ! copp]4 ,! arc flame gives a brilliant :ite light1 &1 simil> to ! m]cury arc1 is inh]5tly limit$ to direct curr5t4 ,x burns 9 ! op5 air at ab\t #ge volts4 ,! lamp is made = #d-;amp]e direct curr5t s]ies circuits & consumes ab\t #caj watts & has an effici5cy ( ab\t #aa lum5s p] watt4 ,illu/ration3 ,,lum9\s ,,or ,,magnetite ,,arc ,,lamp1 #aijb4 ,?is has a negative electrode conta9+ magnetite :i* produces a v lum9\s :ite flame 9 ! arc /ream4 ,! negative 7iron tube7 electrode n[ has a life ( ab\t #cej h\rs4 ,lat]1 a high] effici5cy1 #d-;amp]e electrode 0 made :i* has a %ort] life b gives an effici5cy ( ab\t #ag l-p-w1 & a #f4f-;amp]e lamp 0 also made giv+ an effici5cy ( ab\t #ah l-p-w us+ ! regul> electrode4 ,?is electrode 9 be+ consum$ gives (f fumes1 s ! lamp has a *imney ?r\gh its body to c>ry !m (f4 ,"s ( ! fumes cond5se1 leav+ a f9e p[d]1 iron oxide1 9 ! =m ( ru/4 ,! consumption ( ! positive 7copp]7 electrode is v sl[1 :i* is opposite to t ( c>bon arc lamps on direct curr5t4 ,! arc flame is brighte/ ne> ! negative 7iron tube7 electrode & decreases 9 brilliancy & volume z x ne>s ! positive 7copp]7 electrode4 ,illu/ration3 ,,diagram ,,( ,,s]ies ,,magnetite ,,arc ,,lamp4 ,! me?od ( control1 entirely diff]5t f t ( o!r arc lamps1 0 inv5t$ by ,halvorson to meet ! peculi>ities ( ?is arc4 ,! peculi>ities ( ! arc are su* t ,halvorson inv5t$ an entirely new pr9ciple ( control4 ,! electrodes are normally ap>t4 ,9 />t+1 !y are drawn toge!r by a />t+ magnet ) suffici5t =ce to dislodge ! slag :i* =ms on ! negative electrode & :i* becomes an insulator :5 cold4 ,curr5t !n fl[s ?r\gh ! electrodes & ?r\gh a s]ies magnet :i* pulls up a sol5oid break+ ! circuit ?r\gh ! />t+ magnet4 ,?is all[s ! l[] electrode to fall a fix$ di/ance1 ab\t sev5-eigh?s ( an in*1 draw+ ! arc1 ^: voltage is !n ab\t #gb volts4 ,z ! negative electrode is consum$1 ! l5g? & voltage ( ! arc increases :5 a magnet1 9 %unt ) ! arc1 becomes suffici5tly en]giz$ to close ! contacts 9 ! circuit ( ! />t+ magnet caus+ ! electrode to pick up & />t (f aga94 ,,m]cury ,,arc ,,rectifi] ,,= ,,magnetite ,,arc ,,lamps ,illu/ration3 ,,m]cury ,,arc ,,rectifi] ,,tube ,,= ,,s]ies ,,magnetite ,,arc ,,lamps1 #aijb4 ,! m]cury arc conv]t$ ! alt]nat+ con/ant curr5t into direct curr5t requir$ by ! magnetite lamp4 ,z ! magnetite arc requires direct curr5t = its op]ation1 ! obvi\s way to supply a direct con/ant curr5t = s]ies circuits is to rectify1 by means ( ! m]cury arc1 ! alt]nat+ curr5t obta9$ f a con/ant curr5t trans=m]4 ,! t]m9als ( ! movable second>y coil ( ! con/ant curr5t trans=m] are connect$ to ! two arms ( ! rectifi] tube4 ,"o end ( ! s]ies circuit is connect$ to ! c5t] ( ! second>y coil4 ,! o!r end ( ! s]ies circuit is connect$ to a reactance :i* 9 turn is connect$ to ! pool ( m]cury 9 ! bottom ( ! rectifi] tube4 ,"o-half ( ! cycle ( ! alt]nat+ curr5t goes f ! second>y coil to "o arm ( ! rectifi] tube ?r\gh ! m]cury vapor1 ! m]cury arc hav+ already be5 />t$ by a sep>ate />t+ electrode4 ,x !n goes to ! pool ( m]cury1 ?r\gh ! reactance & ?r\gh ! s]ies circuit4 ,! o!r half cycle ( alt]nat+ curr5t goes to ! o!r arm ( ! rectifi] tube1 ?r\gh ! m]cury vapor1 etc41 & ?r\gh ! s]ies circuit4 ,?us a pulsat+ direct curr5t fl[s ?r\gh ! s]ies circuit1 ! magnetic action ( ! reactance coil mak+ ! pulsations ( curr5t ov]lap ea* o!r1 :i* prev5ts ! m]cury arc f go+ out4 ,illu/ration3 ,,e>ly ,,m]cury ,,arc ,,rectifi] ,,in/allation4 ,,inc&esc5t ,,lamp ,,developm5ts1 #ahid-aijd ,) ! developm5t ( a wat]pro( base 9 #aijj1 by ! use ( a wat]pro( cem5t in/ead ( pla/] ( ,p>is to fa/5 ! base to ! bulb1 porcela9 at fir/ & lat] glass be+ us$ to insulate ! t]m9als ( ! base f ea* o!r1 lamps c\ld be expos$ to ! wea!r & give good results4 ,electric sign light+ !re=e receiv$ a great /imulus1 & lamps z l[ z #b c&lep[] = #aaj volts 7 design$ = ?is purpose4 ,c>bon lamps ) conc5trat$ filam5ts 7 also made = /]eoptican & o!r focuss+ purposes4 ,^! lamps 7 made 9 sizes f #bj to #ajj c&lep[]4 ,! arc lamp 0 m desirable = l>g] units4 ,! dry batt]y 0 made 9 small units ( #b1 #c & #e cells1 s t lamps ( ab\t to #a c&lep[] 7 made = #b1 #c & #f volts1 = portable fla%lights4 ,x 0 n h[ev] until ! tung/5 filam5t 0 develop$ 9 #aijg t ^! fla%lights became z popul> z !y n[ are4 ,= ornam5tal light+1 lamps 7 suppli$ 9 r\nd & tubul> bulbs1 usually fro/$ to s(t5 ! light4 ,illu/ration3 ,,! ,,moore ,,tube ,,light1 #aijd4 ,?is consi/$ ( a tube ab\t #a in*es 9 diamet] & hav+ a l5g? up to #bjj feet1 9 :i* air at ab\t "o ?\s&? "p ( atmosph]ic pressure 0 made to gl[ by a v high voltage alt]nat+ curr5t4 ,,! ,,moore ,,tube ,,light ,geissl]1 a ,g]man1 discov]$ sixty odd ye>s ago1 t a high voltage alt]nat+ curr5t w\ld cause a vacuum tube to gl[4 ,?is light 0 simil> to t obta9$ by ,hawksbee ov] two hundr$ ye>s ago4 ,geissl] obta9$ 8 high voltage alt]nat+ curr5t by a sp>k coil1 :i* consi/$ ( two coils ( wire m\nt$ on an iron core4 ,curr5t f a prim>y batt]y pass$ ?r\gh ! prim>y coil1 & ?is curr5t 0 rapidly int]rupt$ by a vibrator on ! pr9ciple ( an electric bell4 ,?is induc$ an alt]nat+ curr5t ( high voltage 9 ! second>y coil z ?is coil _h a great _m m turns ?an ! prim>y coil _h4 ,sci5ti/s f\nd t ab\t #gj p] c5t ( ! electrical en]gy put into ! ,geissl] tube 0 conv]t$ into ! actual en]gy 9 ! light giv5 out4 ,9 #ahia ,mr4 ,d4 ,mc,farlan ,moore1 an ,am]ican1 impress$ ) ! fact t only "o-half ( "o p] c5t ( ! electrical en]gy put into ! c>bon-inc&esc5t lamp came out 9 ! =m ( light1 decid$ to inve/igate ! possibilities ( ! vacuum tube4 ,aft] sev]al ye>s ( exp]im5ts & ! mak+ ( _m trial lamps1 he f9ally1 9 #aijd1 made a lamp t 0 comm]cially us$ 9 consid]able numb]s4 ,illu/ration3 ,,diagram ,,( ,,fe$] ,,valve ,,( ,,moore ,,tube4 ,z ! c>bon t]m9als inside ! tube absorb$ ! v slight am\nt ( gas 9 ! tube1 a fe$] valve all[$ gas to fl[ 9 ! tube1 regulat+ ! pressure to )9 "o t5 ?\s&? "p ( an atmosph]e above & bel[ ! normal extremely slight pressure requir$4 ,! fir/ in/allation ( ?is =m ( lamp 0 9 a h>dw>e /ore 9 ,new>k1 ,n4 ,j4 ,x consi/$ ( a glass tube #a in*es 9 diamet] & #ahj feet long4 ,air1 at a pressure ( ab\t "o-?\s& "p ( an atmosph]e1 0 9 ! tube1 f :i* 0 obta9$ a pale p9k color4 ,high voltage 7ab\t #af1jjj volts7 alt]nat+ curr5t 0 suppli$ by a trans=m] to two c>bon electrodes inside ! ends ( ! tube4 ,! air _h to be ma9ta9$ )9 "o t5-?\s&? "p ( atmosph]ic pressure above & bel[ ! normal ( "o-?\s&?1 & z ! r>efi$ air 9 ! tube comb9$ *emically ) ! c>bon electrodes1 means _h to be devis$ to ma9ta9 ! air 9 ! tube at ?is slight pressure z well z )9 ! n>r[ limits requir$4 ,?is 0 accompli%$ by a piece ( c>bon ?r\gh :i* ! air c\ld seep1 b if cov]$ ) m]cury w\ld make a tight seal4 ,z ! air pressure became l[1 an increas$ curr5t w\ld fl[ ?r\gh ! tube1 ! normal be+ ab\t a t5? ( an amp]e4 ,?is accord+ly increas$ ! curr5t fl[+ ?r\gh ! prim>y coil ( ! trans=m]4 ,9 s]ies ) ! prim>y coil 0 an electro-magnet :i* lift$1 z ! curr5t increas$1 a bundle ( iron wires m\nt$ 9 a glass tube :i* float$ 9 m]cury4 ,! glass tube1 ris+1 l[]$ ! height ( ! m]cury1 uncov]+ a c>bon rod cem5t$ 9 a tube connect+ ! ma9 tube ) ! op5 air4 ,?us air c\ld seep ?r\gh ?is c>bon rod until ! prop] am\nt 0 f$ into ! ma9 tube4 ,:5 ! curr5t came back to normal ! electro-magnet l[]$ ! float+ glass tube :i* rais$ ! height ( ! m]cury & cov]$ ! c>bon rod1 ?us %utt+ (f ! fur!r supply ( air4 ,z !re 0 a con/ant loss ( ab\t #djj watts 9 ! trans=m]1 & an additional loss ( ab\t #bej watts 9 ! two electrodes1 ! total consumption ( ! #ahj-;foot tube 0 ab\t #bbej watts4 ,nitrog5 gas gave a yell[ light1 :i* 0 m effici5t & s 0 lat] us$4 ,on acc\nt ( ! fix$ losses 9 ! trans=m] & electrodes ! long] tubes 7 m effici5t1 ?\gh !y 7 made 9 v>i\s sizes ( f #dj to #bjj feet4 ,! #bjj-;foot tube1 ) nitrog51 _h an effici5cy ( ab\t #aj lum5s p] watt4 ,nitrog5 gas 0 suppli$ to ! tube by remov+ ! oxyg5 f ! air us$4 ,?is 0 accompli%$ by pass+ ! air ov] phosphor\s :i* absorb$ ! oxyg54 ,c>bon dioxide gas 7,,co#b7 gave a pure :ite light b at ab\t half ! effici5cy ( nitrog54 ,! gas 0 obta9$ by all[+ hydro*loric acid to come 9 contact ) lumps ( m>ble 7calcium c>bonate7 :i* set free c>bon dioxide & wat] vapor4 ,! latt] 0 absorb$ by pass+ ! gas ?r\gh lumps ( calcium *loride4 ,! c>bon dioxide tube on acc\nt ( its daylight color value1 made an excell5t light "u :i* accurate color mat*+ c\ld be done4 ,a %ort tube is made = ?is purpose & ?is is ! only use :i* ! ,moore tube n[ has1 ow+ to ! m effici5t & simpl] tung/5 filam5t inc&esc5t lamp4 ,,! ,,osmium ,,lamp ,dr4 ,au] von ,welsba*1 ! ,g]man sci5ti/ :o _h produc$ ! ,welsba* gas mantle1 inv5t$ an inc&esc5t electric lamp hav+ a filam5t ( ! metal osmium4 ,x 0 comm]cially introduc$ 9 ,europe 9 #aije & a few 7 sold1 b x 0 nev] m>ket$ 9 ?is c\ntry4 ,x 0 g5]ally made = #ee volts1 two lamps to burn 9 s]ies on #aaj-volt circuits1 gave ab\t #be c&lep[] & _h an initial effici5cy ( ab\t #e lum5s p] watt4 ,x _h a v fair ma9t5ance ( c&lep[] dur+ its life1 hav+ an av]age effici5cy ( ab\t #e l-p-w4 ,osmium is a v r>e & exp5sive metal1 usually f\nd associat$ ) plat9um1 & is !re=e v difficult to obta94 ,burnt out lamps 7 !re=e b\ght back 9 ord] to obta9 a supply ( osmium4 ,x is also a v brittle metal1 s t ! lamps 7 extremely fragile4 ,illu/ration3 ,,osmium ,,lamp1 #aije4 ,?is inc&esc5t lamp 0 us$ 9 ,europe = a few ye>s1 b 0 impractical to manufacture 9 l>ge quantities z osmium is r>] & m exp5sive ?an plat9um4 ,,! ,,gem ,,lamp ,dr4 ,willis ,r4 ,:itney1 ( ,s*5ectady1 ,n4 ,y41 _h inv5t$ an electrical resi/ance furnace4 ,?is consi/$ ( a holl[ c>bon tube1 pack$ 9 s&1 ?r\gh :i* a v heavy curr5t c\ld be pass$4 ,?is heat$ ! tube to a v high temp]ature1 ! s& prev5t+ ! tube f oxidiz+1 s t :atev] 0 put inside ! tube c\ld be heat$ to a v high heat4 ,among 8 v>i\s exp]im5ts1 he heat$ "s c>bon filam5ts & f\nd t ! high temp]ature *ang$ _! resi/ance 8*>act]i/ic0 f negative to positive4 ,! ord9>y c>bon filam5t has a resi/ance :5 hot t is less ?an :5 x is cold1 :i* 0 rev]s$ aft] heat+ x to ! high temp]ature ,dr4 ,:itney 0 able to obta94 ,^! filam5ts 7 made into lamps = #aaj-volt s]vice & x 0 f\nd t !y c\ld be op]at$ at an effici5cy ( #d lum5s p] watt4 ,! lamps also black5$ less ?an ! regul> c>bon lamp ?r\gh\t _! life4 ,illu/ration3 ,,gem ,,lamp1 #aije4 ,?is inc&esc5t lamp _h a graphitiz$ c>bon filam5t obta9$ by ! heat ( an electric furnace1 s t x c\ld be op]at$ at #be p] c5t high] effici5cy ?an ! regul> c>bon lamp4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,?is lamp 0 put on ! m>ket 9 #aije & 0 call$ ! ,gem or metalliz$ c>bon filam5t lamp z su* a c>bon filam5t _h a resi/ance *>act]i/ic simil> to metals4 ,at fir/ x _h two s+le hair p9 filam5ts 9 s]ies :i* 9 #aiji 7 *ang$ to a s+le loop filam5t l ! c>bon lamp4 ,9 #aije ! rat+ ( inc&esc5t lamps 0 *ang$ f a c&lep[] to a wattage basis4 ,! ord9>y #af-;c&lep[] c>bon lamp consum$ #ej watts & 0 s rat$4 ,! #ej-watt ,gem lamp gave #bj c&lep[]1 bo? c&lep[] rat+s be+ _! mean c&lep[] 9 a horizontal direction4 ,! ,gem lamp 0 made = #aaj-volt circuits 9 sizes f #dj to #bej watts4 ,! #ej-watt size 0 ! mo/ popul>1 _m millions ( :i* 7 made be=e ! lamp disappe>$ f use 9 #aiah4 ,! lamp 0 n q z /rong z ! c>bon lamp4 ,"s ,gem lamps = s]ies circuits 7 also made1 b ^! 7 soon sup]s$$ by ! tung/5-filam5t lamp :i* appe>$ 9 #aijg4 ,,! ,,tantalum ,,lamp ,illu/ration3 ,,tantalum ,,lamp1 #aijf4 ,! tantalum filam5t c\ld be op]at$ at #ej p] c5t great] effici5cy ?an t ( ! regul> c>bon inc&esc5t lamp4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,dr4 ,w]n] von ,bolton1 a ,g]man physici/1 made an inve/igation ( v>i\s mat]ials to see if any ( !m 7 m suitable ?an c>bon = an inc&esc5t-lamp filam5t4 ,aft] exp]im5t+ ) v>i\s metals1 tantalum 0 tri$4 ,tantalum _h be5 kn[n to sci5ce = ab\t a hundr$ ye>s4 ,von ,bolton f9ally obta9$ "s ( ! pure metal & f\nd x to be ductile s t x c\ld be drawn out into a wire4 ,z x _h a l[ specific resi/ance1 ! wire filam5t _h to be mu* long] & ?9n] ?an ! c>bon filam5t4 ,a great numb] ( exp]im5tal lamps 7 made s t x 0 n until #aijf t ! lamp 0 put on ! m>ket 9 ?is c\ntry4 ,x _h an initial effici5cy ( #e lum5s p] watt & a good ma9t5ance ( c&le p[] ?r\gh\t its life1 hav+ an av]age effici5cy ( ab\t #d l-p-w4 ,! usual sizes ( lamps 7 #dj & #hj watts giv+ ab\t #bj & #dj c&lep[] respectively4 ,x 0 n q z /rong z ! c>bon lamp1 & on alt]nat+ curr5t ! wire cry/alliz$ m rapidly1 s t x broke m easily1 giv+ a %ort] life ?an on direct curr5t4 ,x disappe>$ f use 9 #aiac4 ,,inv5tion ,,( ,,! ,,tung/5 ,,lamp ,alex&] ,j & ,franz ,hanaman 9 #aijb 7 laboratory assi/ants to ! ,pr(essor ( ,*emi/ry 9 ! ,te*nical ,high ,s*ool 9 ,vi5na4 ,j 0 sp5d+ 8 sp>e "t 9 ano!r laboratory 9 ,vi5na1 attempt+ to develop a boron inc&esc5t lamp4 ,9 ,augu/ ( t ye> he engag$ ,hanaman to aid him 9 8 "w4 ,!y conceiv$ ! idea ( mak+ a lamp ) a filam5t ( tung/5 & = two ye>s work$ on bo? lamps4 ,! boron lamp turn$ out to be a failure4 ,_! means 7 limit$2 ,hanaman's total income 0 #dd p] mon? & ,j's 0 slightly m ?an ?is4 ,9 #aijc !y took out a ,g]man pat5t on a tung/5 filam5t1 b ! process !y describ$ 0 a failure because x produc$ a filam5t conta9+ bo? c>bon & tung/54 ,! c>bon readily evaporat$ & quickly black5$ ! bulb :5 !y attempt$ to op]ate ! filam5t at an effici5cy high] ?an t possible ) ! ord9>y c>bon filam5t4 ,f9ally 9 ! latt] "p ( ! next ye> 7#aijd7 !y 7 able to get rid ( ! c>bon & produc$ a pure tung/5 filam5t4 ,tung/5 _h be5 kn[n to *emi/s = _m ye>s by its comp\nds1 its oxides & its alloys ) /eel1 b ! prop]ties ( ! pure metal 7 practically unkn[n4 ,x is an extremely h>d & brittle metal & x 0 impossible at t "t to draw x into a wire4 ,j & ,hanaman's process ( mak+ a pure tung/5 filam5t consi/$ ( tak+ tung/5 oxide 9 ! =m ( an extremely f9e p[d]1 r$uc+ ?is to pure tung/5 p[d] by heat+ x :ile hydrog5 gas pass$ ov] x4 ,! gas comb9$ ) ! oxyg5 ( ! oxide1 =m+ wat] vapor :i* 0 c>ri$ (f1 leav+ ! tung/5 beh9d4 ,! tung/5 p[d] 0 mix$ ) an organic b9d+ mat]ial1 & ! pa/e 0 =c$ by v high pressure ?r\gh a hole drill$ 9 a diamond4 ,?is diamond die 0 necess>y because tung/51 be+ s h>d a sub/ance1 w\ld quickly we> away any o!r k9d ( die4 ,! ?read =m$ 0 cut into prop] l5g?s1 b5t ! %ape ( a hair p9 & ! ends fa/5$ to clamps4 ,curr5t 0 pass$ ?r\gh ! hair p9 9 ! pres5ce ( hydrog5 gas & wat] vapor4 ,! curr5t heat$ ! hair p91 c>boniz$ ! organic b9d+ mat]ial 9 x1 ! c>bon !n comb9+ ) ! moi/ hydrog5 gas1 leav+ ! tung/5 p>ticles beh9d4 ,^! p>ticles 7 s9t]$ toge!r by ! heat1 =m+ ! tung/5 filam5t4 ,pat5ts 7 appli$ = 9 v>i\s c\ntries1 ! "o 9 ! ,unit$ ,/ates on ,july #f1 #aije4 ,! two laboratory assi/ants 9 #aije f9ally succe$$ 9 gett+ _! inv5tion tak5 up by a ,hung>ian lamp manufactur]4 ,by ! end ( ! ye> lamps 7 made t 7 a /rik+ success = !y c\ld be op]at$ at an effici5cy ( #h lum5s p] watt4 ,!y 7 put on ! ,am]ican m>ket 9 #aijg1 ! fir/ lamp put out be+ ! #ajj-watt size = #aaj-volt circuits4 ,?is 0 done by m\nt+ sev]al hair p9 loops 9 s]ies to get ! requisite resi/ance1 tung/5 hav+ a l[ specific resi/ance4 ,! issue ( ! ,am]ican pat5t 0 delay$ ow+ to an int]f]5ce betwe5 f\r diff]5t p>ties1 ea* claim+ to be ! inv5tor4 ,aft] prolong$ he>+s1 "o application hav+ be5 f\nd to be fraudul5t1 ! pat5t 0 f9ally grant$ to ,j & ,hanaman on ,febru>y #bg1 #aiab4 ,illu/ration3 ,,tung/5 ,,lamp1 #aijg4 ,! orig9al #ajj watt tung/5 lamp 0 ne>ly ?ree times z effici5t z ! c>bon lamp1 b its 8press$0 filam5t 0 v fragile4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,?is 8press$0 tung/5 filam5t 0 q fragile1 b on acc\nt ( its relatively high effici5cy comp>$ ) o!r inc&esc5t lamps1 x imm$iately became popul>4 ,soon aft] its introduction x became possible to make f9] filam5ts s t lamps = #fj1 #dj & !n #be watts = #aaj-volt circuits 7 made available4 ,sizes up to #ejj watts 7 also made :i* soon began to displace ! enclos$ c>bon arc lamp4 ,lamps 7 also made = s]ies circuits 9 sizes f #cb to #djj c&lep[]4 ,^! promptly displac$ ! c>bon & ,gem s]ies lamps4 ,! high effici5cy ( ! tung/5 filam5t 0 a great /imulus to fla%lights :i* are n[ sold by ! millions ea* ye>4 ,! light+ ( railroad c>s1 ,pullmans & coa*es1 ) tung/5 lamps obta9+ _! curr5t f /orage batt]ies1 soon sup]s$$ ! gas light =m]ly us$4 ,9 "s cases1 a dynamo1 run by a belt f ! c> axle1 kept ^! batt]ies *>g$4 ,illu/ration3 ,,drawn ,,tung/5 ,,wire ,,lamp1 #aiaa4 ,sci5ti/s _h decl>$ x impossible to *ange tung/5 f a brittle to ductile metal4 ,?is1 h[ev]1 0 accompli%$ by ,dr4 ,coolidge1 & drawn tung/5 wire made ! lamp v /urdy4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,,drawn ,,tung/5 ,,wire ,aft] sev]al ye>s ( pati5t exp]im5t1 ,dr4 ,william ,d4 ,coolidge 9 ! rese>* laboratory ( a l>ge electrical manufactur+ company at ,s*5ectady1 ,n4 ,y41 inv5t$ a process = mak+ tung/5 ductile1 a pat5t = :i* 0 obta9$ 9 ,decemb]1 #aiac4 ,tung/5 _h h]et(ore be5 kn[n z a v brittle metal1 b by means ( ?is process x became possible to draw x into wire4 ,?is greatly simplifi$ ! manufacture ( lamps & enorm\sly improv$ _! /r5g?4 ,su* lamps 7 comm]cially introduc$ 9 #aiaa4 ,) drawn tung/5 wire x 0 easi] to coil & !re=e conc5trate ! filam5t z requir$ by focus+ types ( lamps4 ,! automobile headlight lamp 0 among ! fir/ ( ^!1 :i* 9 #aiab />t$ ! comm]cial use ( electric light on c>s 9 place ( oil & acetyl5e gas4 ,on /reet railway c>s ! use ( tung/5 lamps1 made possible on ?is sev]e s]vice by ! great] /urd9ess ( ! drawn wire1 greatly improv$ _! light+4 ,fur!rmore1 z ! voltage on /reet railway sy/ems is subject to great *anges1 ! c&lep[] ( ! tung/5 filam5t has ! advantage ( v>y+ b ab\t half z mu* z t ( ! c>bon lamp on fluctuat+ voltage4 ,illu/ration3 ,,qu>tz ,,m]cury ,,vapor ,,lamp1 #aiab4 ,! m]cury arc if enclos$ 9 qu>tz glass c be op]at$ at mu* high] temp]ature & !re=e great] effici5cy4 ,! light is /ill defici5t 9 r$ b gives a consid]able am\nt ( ultra-violet rays :i* kill bact]ia & are v dang]\s to ! eye4 ,!y c1 h[ev]1 be absorb$ by a glass globe4 ,! lamp is n us$ z an illum9ant 9 ?is c\ntry1 b is valuable = use 9 ! purification ( wat]4 ,,! ,,qu>tz ,,m]cury ,,vapor ,,arc ,,lamp ,by putt+ a m]cury arc 9 a tube made ( qu>tz in/ead ( glass1 x c be op]at$ at a mu* high] temp]ature & !reby obta9 a great] effici5cy4 ,su* a lamp1 h[ev]1 is /ill l>gely defici5t 9 r$ rays1 & x gives out a consid]able am\nt ( ultra-violet rays4 ,^! ultra-violet rays w kill bact]ia & ! lamp is be+ us$ to a c]ta9 ext5t = su* purpose z 9 ! purification ( wat]4 ,^! rays are v dang]\s to ! eyes1 b !y are absorb$ by glass1 s z an illum9ant1 a glass globe mu/ be us$ on ! lamp4 ,^! lamps appe>$ 9 ,europe ab\t #aiab b 7 nev] us$ to any ext5t 9 ?is c\ntry z an illum9ant4 ,!y h an effici5cy ( ab\t #bf lum5s p] watt4 ,qu>tz is v difficult to "w1 s ! co/ ( a qu>tz tube is v great4 ,! ord9>y buns5 gas flame is us$ ) glass1 b qu>tz w only become s(t 9 an oxy-hydrog5 or oxy-acetyl5e flame4 ,illu/ration3 ,,gas ,,fill$ ,,tung/5 ,,lamp1 #aiac4 ,by op]at+ a coil$ filam5t 9 an in]t gas1 ,dr4 ,langmuir 0 able to greatly increase its effici5cy1 ! ga9 9 light by ! high] temp]ature p]missible1 m ?an (fsett+ ! loss ( heat by convection ( ! gas4 ,?is lamp is 9 ! exhibit ( ,edison lamps 9 ! ,smi?sonian ,in/itution4 ,,! ,,gas-,,fill$ ,,tung/5 ,,lamp ,! high] ! temp]ature at :i* an inc&esc5t lamp filam5t c be op]at$1 ! m effici5t x becomes4 ,! limit 9 temp]ature is rea*$ :5 ! mat]ial beg9s to evaporate rapidly1 :i* black5s ! bulb4 ,! filam5t becom+ ?9n] m quickly1 ?us ruptur+ soon]1 %ort5s ! life4 ,if1 !re=e1 ! evaporat+ temp]ature c by "s means be slightly rais$1 ! effici5cy w be greatly improv$4 ,?is 0 accompli%$ by ,dr4 ,irv+ ,langmuir 9 ! rese>* laboratories at ,s*5ectady1 ,n4 ,y41 by op]at+ a tung/5 filam5t 9 an in]t gas4 ,nitrog5 0 fir/ us$4 ,! gas circulat+ 9 ! bulb has ! disadvantage ( conduct+ heat away f ! filam5t s t ! filam5t 0 coil$4 ,?is pres5t$ a small] surface to ! curr5ts ( gas & !reby r$uc$ ?is loss4 ,! lamps 7 comm]cially introduc$ 9 #aiac & a pat5t 0 grant$ 9 ,april1 #aiaf4 ,illu/ration3 ,,gas ,,fill$ ,,tung/5 ,,lamp1 #aibc4 ,?is is ! =m ( ! lamp z at pres5t made4 ,= #aaj-volt circuits ! sizes range f #ej to #ajjj watts4 ,an increas$ am\nt ( electrical en]gy is requir$ 9 ^! lamps to (fset ! heat be+ conduct$ away by ! gas4 ,?is heat loss is m9imiz$ 9 a vacuum lamp1 ! filam5t t5d+ to /ay hot on ! pr9ciple ( ! vacuum bottle4 ,?is loss 9 a gas fill$ lamp becomes relatively great 9 a filam5t ( small diamet]1 z ! surface 9 proportion to ! volume ( ! filam5t increases ) decreas+ diamet]s4 ,h5ce !re is a po9t :]e ! ga9 9 temp]ature is (fset by ! heat loss4 ,! fir/ lamps made 7 ( #gej & #ajjj watts = #aaj-volt circuits4 ,lat] #ejj- & !n #djj-watt lamps 7 made4 ,! use ( argon gas1 :i* has a poor] heat conductivity ?an nitrog51 made x possible to produce small] lamps1 #ej-watt gas-fill$ lamps = #aaj-volt circuits n[ be+ ! smalle/ available4 ,9 ! pres5t /ate ( ! art1 a vacuum lamp is m effici5t ?an a gas-fill$ lamp hav+ a filam5t small] ?an "o consum+ ab\t half an amp]e4 ,?us gas-fill$ lamps are n n[ practicable mu* bel[ #ajj watts = #bbj volts1 #ej watts = #aaj volts1 #be watts = #fj volts1 #ae watts = #cj volts1 etc4 ,f ! =ego+ x w be se5 t ! effici5cy ( ^! lamps dep5ds l>gely on ! diamet] ( ! filam5t4 ,!re are o!r consid]ations1 :i* also apply to vacuum lamps1 t affect ! effici5cy4 ,"s ( ^! are3 ! numb] ( an*ors us$1 z !y conduct heat away2 9 v l[ voltage lamps hav+ %ort filam5ts ! relative am\nt ( heat conduct$ away by ! lead+-9 wires becomes ( increas+ importance1 etc4 ,! #ajjj-watt lamp = #aaj-volt circuits is n[ made = ne>ly #bj lum5s p] watt2 ! #ej-watt lamp a little ov] #aj l-p-w4 ,! adv5t ( ! tung/5 filam5t & especially ! gas-fill$ lamp s\nd$ ! doom ( all o!r electric illum9ants except ! magnetite & m]cury arc lamps4 ,all o!r inc&esc5t lamps h n[ practically disappe>$4 ,! flame arc z well z ! enclos$ c>bon arc lamp are h>dly ev] se54 ,! simplicity ( ! inc&esc5t lamp1 its cleanl9ess1 l[ fir/ co/1 l[ ma9t5ance co/ & high effici5cy ( ! tung/5 filam5t h be5 ! ma9 reasons = its popul>ity4 ,,types ,,& ,,sizes ,,( ,,tung/5 ,,lamps ,,n[ ,,made ,!re are ab\t two hundr$ diff]5t types & sizes ( tung/5 filam5t lamps n[ /&>d = v>i\s k9ds ( light+ s]vice4 ,= #aaj-volt s]vice1 lamps are made 9 sizes f #aj to #ajjj watts4 ,( ! small] sizes1 "s are made 9 r\nd & tubul>-%ap$ bulbs = ornam5tal light+4 ,9 addition !re are ! c&elabra lamps us$ 9 ornam5tal fixtures4 ,tw5ty-five- to five hundr$-watt lamps are made ) bulbs ( special blue glass to cut out ! excess ( r$ & yell[ rays & ?us produce a light approximat+ daylight4 ,= #bbj-volt s]vice lamps are made 9 sizes ( f #be to #ajjj watts4 ,= sign light+ s]vice1 #e-watt lamps ( l[ voltage are made = use on a trans=m] locat$ ne> ! sign to r$uce ! #aaj volts alt]nat+ curr5t to t requir$ by ! lamps4 ,lamps are made f #e to #ajj watts = #cj-volt s]vice1 su* z is f\nd 9 tra9 light+ & 9 gas eng9e driv5 dynamo sets us$ 9 rural homes beyond ! rea* ( c5tral /ation sy/ems4 ,conc5trat$ filam5t lamps are made = /]eopticon & motion picture projection1 floodlight+1 etc41 9 sizes f #ajj to #ajjj watts1 = /reet railway headlights 9 sizes bel[ #ajj watts & = locomotive headlights 9 sizes f #ajj to #bej watts4 ,= s]ies circuits1 us$ 9 /reet light+1 lamps are made f #fj to #bejj c&lep[]4 ,m9iature lamps cov] ^? = fla%light1 automobile1 ,*ri/mas-tree1 surgical & d5tal s]vices1 etc4 ,!y range1 dep5d+ on ! s]vice1 f to #ba c&lep[]1 & 9 voltage f #b to #bd4 ,illu/ration3 ,,/&>d ,,tung/5 ,,lamps1 #aibc4 ,?is illu/rates "s ( ! two hundr$ diff]5t lamps regul>ly made4 ,,/&>d ,,voltages ,m5tion has be5 made ( #aaj-volt s]vice1 #bbj-volt s]vice1 etc4 ,9 ! days ( ! c>bon inc&esc5t lamp x 0 impossible to manufacture all lamps = an exact pr$et]m9$ voltage4 ,! popul> voltage 0 #aaj1 s light+ companies 7 reque/$ 9 a numb] ( in/ances to adju/ _! s]vice to "s voltage o!r ?an #aaj4 ,!y 7 ?us able to utilize ! odd voltage lamps manufactur$1 & ?is produc$ a dem& = lamps ( v>i\s voltages f #ajj to #acj4 ,arc lamps _h a resi/ance 7reactance on alt]nat+ curr5t7 t 0 adju/able = voltages betwe5 #ajj & #acj4 ,simil>ly a dem& 0 creat$ = lamps ( individual voltages ( f #bjj to #bfj4 ,! #bjj- to #bfj-volt range has simm]$ d[n to #bbj1 #bcj1 #bdj & #bej volts4 ,^! lamps are n z effici5t z ! #aaj-volt type & _! dem& is consid]ably less1 z ! #aaj-volt class ( s]vice = light+ is1 ) ! exception ( ,engl&1 almo/ univ]sal4 ,?us #aaj-volt s]vice means #ajj to #acj volts 9 contra-di/9ction to #bjj to #bfj volts1 etc4 ,! drawn tung/5 wire filam5t made x possible to accurately pr$et]m9e ! voltage ( ! lamp1 s n[ t ! c>bon inc&esc5t lamp is a ?+ ( ! pa/1 !re is no ne$ = s _m diff]5t voltages4 ,sev]al ye>s ago /&>d voltages ( #aaj1 #aae & #abj 7 recomm5d$ = adoption by all ! electrical societies 9 ! ,unit$ ,/ates1 & practically all c5tral /ations h n[ *ang$ _! s]vice to "o ( ^! voltages4 ,,co/ ,,( ,,inc&esc5t ,,electric ,,light ,9 ! e>ly '#hj's curr5t 0 exp5sive1 co/+ a consum] on ! av]age ab\t tw5ty c5ts p] kil[att h\r4 ,! co/ has gradually come d[n & ! g5]al av]age rate = :i* curr5t is sold = light+ purposes is n[ ab\t #d c5ts4 ,dur+ ! p]iod #ahhj to #aije ! av]age effici5cy ( c>bon lamps ?r\gh\t _! life increas$ f ab\t "o to ov] #b lum5s p] watt & _! li/ price decreas$ f "o doll> to tw5ty c5ts4 ,! av]age am\nt ( light obta9$ = "o c5t at fir/ 0 ab\t five c&lep[] h\rs & 9 #aijd x 0 increas$ to ov] ?irty-six at ! av]age rate !n 9 effect4 ,! next ye> ) ! m effici5t ,gem lamp #dd c&le-h\rs c\ld be _h = "o c5t4 ,9 #aijf ! am\nt 0 increas$ to #ej ) ! tantalum lamp & ) ! tung/5 lamp 9 #aijg1 ev5 at its high price ( #a4ej1 ! am\nt 0 fur!r increas$ to #fc4 ,s9ce !n ! av]age co/ ( curr5t has be5 r$uc$ b slightly1 b ! effici5cy ( ! tung/5 lamp has mat]ially increas$ & its co/ r$uc$ s t x is n[ possible to obta91 ) ! ord9>y #dj-watt lamp #agj c&le-h\rs = a c5t4 ,if ! gas-fill$ tung/5 lamp 7 us$ ! am\nt ( light n[ obta9$ = a c5t w\ld dep5d ^u ! size1 :i*1 = ! #ajjj-watt lamp1 w\ld be #chb c&le-h\rs4 ,,/ati/ics ,,reg>d+ ,,! ,,pres5t ,,dem& ,,= ,,lamps ,9 ! ,unit$ ,/ates !re are ab\t #cej million inc&esc5t & ab\t two hundr$ ?\s& magnetite arc lamps n[ 7#aibc7 9 use4 ,!y are increas+ ab\t #aj p] c5t ea* ye>4 ,! annual dem& = inc&esc5t lamps = r5ewals & new in/allations is ov] #bjj millions1 exclusive ( m9iature lamps4 ,! use ( inc&esc5t lamps 9 all o!r c\ntries put toge!r is ab\t equal t 9 ! ,u4 ,s4 ,! av]age c&lep[] ( /&>d light+ lamps has increas$ f #af1 :i* prevail$ dur+ ! p]iod prior to #aije1 to ov] #fj4 ,! av]age wattage has n v>i$ mu* dur+ ! pa/ tw5ty-odd ye>s1 ! av]age lamp n[ consum+ ab\t #ee watts4 ,?is indicates t ! public is utiliz+ ! improvem5t 9 lamp effici5cy by increas$ illum9ation4 ,! pres5t mo/ popul> lamp is ! #dj-watt size :i* repres5ts #bj p] c5t ( ! total dem&4 ,second 9 dem& is ! #be-watt at #ah p] c5t & ?ird1 ! #ej-watt at #ae p] c5t ( ! total 9 numb]s4 ,:ile ! aggregate dem& ( all ! gas-fill$ tung/5 lamps is a little ov] #bj p] c5t 9 numb]s1 !y repres5t1 on acc\nt ( _! great] effici5cy & wattage1 ov] half ! am\nt ( total c&lep[] us$4 ,9 ! ,unit$ ,/ates ab\t #he p] c5t ( all lamps are = ! #aaj-volt range4 ,ab\t #e p] c5t = #bbj volts1 #b p] c5t = /reet s]ies light+1 #c p] c5t = /reet railway & #e p] c5t = tra9light+ & miscellane\s classes ( s]vice4 ,,select$ ,,bibliography ,,alglave ,,& ,,b\l>d1 8,! ,electric ,light10 translat$ by ,t4 ,o',connor ,sloane1 edit$ by ,c4 ,m4 ,lungr51 ,d4 ,appleton ,co41 ,new ,york1 #ahhd4 ,,b>ham1 ,g4 ,,basil1 8,! ,developm5t ( ! ,inc&esc5t ,electric ,lamp10 ,scott ,gre5wood ,son1 ,london1 #aiab4 ,,dr$ge1 ,,james1 8,electric ,illum9ation10 #b vols41 ,john ,wiley ,sons1 ,new ,york1 #ahhb4 ,,durg91 ,,william ,a41 8,electricity--,its ,hi/ory & ,developm5t10 ,a4 ,c4 ,mc,clurg ,co41 ,*icago1 #aiab4 ,,dy] ,,m>t91 8,edison1 ,8 ,life & ,inv5tions10 #b vols41 ,h>p] ,bros41 ,new ,york1 #aiaj4 ,,guillem91 ,,am$ee1 8,electricity & ,magnetism10 edit$ by ,silvanus ,p4 ,?ompson1 ,mc,millan ,co41 ,london1 #ahia4 ,,h\/on1 ,,edw9 ,j41 8,electricity ,"o ,hundr$ ,ye>s ago & ,to-day10 ,! ,w4 ,j4 ,john/on ,co41 ,new ,york1 #ahid4 ,,h\/on ,,& ,,k5nelly1 8,electric ,arc ,light+10 ,mc,graw ,publi%+ ,co41 ,new ,york1 #aijf4 ,,hut*9son1 ,,roll9 ,w41 ,,jr41 8,high ,effici5cy ,electrical ,illum9ants & ,illum9ation10 ,john ,wiley ,sons1 ,new ,york1 #aiaa4 ,,mai]1 ,,julius1 8,arc & ,gl[ ,lamps10 ,:ittak] ,co41 ,london1 #ahhf4 ,,pope1 ,,frankl9 ,,leon>d1 8,evolution ( ! ,electric ,inc&esc5t ,lamp10 ,bos*5 ,wef]1 ,new ,york1 #ahid4 ,,solomon1 ,,maurice1 8,electric ,lamps10 ,d4 ,van ,no/r& ,co41 ,new ,york1 #aijh4 ,transcrib]'s ,notes ,punctuation1 hyph5ation1 & spell+ 7 made consi/5t :5 a pr$om9ant pref]5ce 0 f\nd 9 ! orig9al book2 o!rwise !y 7 n *ang$4 ,simple typographical errors 7 correct$2 unbalanc$ quotation m>ks 7 rem$i$ :5 ! *ange 0 obvi\s1 & o!rwise left unbalanc$4 ,illu/rations 9 ?is e,book h be5 position$ betwe5 p>agraphs4 ,9 v]sions ( ?is e,book t support hyp]l9ks1 ! page ref]5ces 9 ! ,li/ ( ,illu/rations lead to ! correspond+ illu/rations4 8,alles&ro ,volta0 0 pr9t$ t way4